Chapter 4

Bletchley Park

AGD and his family had moved to Ashtead in Surrey in 1937. They enjoyed their tall, thin house at 48 Tedworth Square, Chelsea, and AGD had a twenty-year lease on the property. They also had a bungalow, called Greengates, in Fairfield Road, Barton-on-Sea, Hampshire, where they spent the summers. They went to the beach twice a day and AGD enjoyed building sandcastles and paddling in the shallows. He also played golf nearby with his son, but AGD was not good at small talk and conversation was restricted to golfing matters. The move was prompted by Robin’s poor health and the same year they holidayed in St. Malo and Dinard in France. The Dennistons were a nuclear family and AGD usually partnered his daughter ‘Y’ when they played bridge, while his son Robin partnered his mother. The family played tennis in Chelsea and used public courts in Bletchley and Ashtead, Robin describing AGD as being ‘small but nippy and devious and could do spin shots which the straightforward players of those days found hard to return’. AGD and Dorothy talked endlessly about the children in the evenings. In 1938, they went to Scotland, borrowing a disused cottage half-way up Loch Striven in South Argyllshire, only a few miles from where AGD’s father had practised medicine. Their cottage could only be accessed by boat. AGD loved boats and the sea, having been brought up amongst them at Dunoon. Their party included a German, Ian Schiller, who had ‘adopted’ the Dennistons and made ‘Y’ his ‘honorary’ goddaughter. Although partially lame, he was adept on boats, which was helpful, given that all of their holiday effects needed to be transported to their holiday cottage by boat. AGD had to hurry back to London, leaving the family in Schiller’s care. In 1939, the family spent several weekends at Barton-on-Sea, having sold the bungalow in Fairfield Road. That summer they were holidaying in Fowey in Cornwall when, once again, AGD had to suddenly rush back to London.

On 1 August 1939, Sinclair had ordered the Service sections of GC&CS to take up their war stations at BP. The Diplomatic and Commercial Sections were ordered to move to BP on 15 August. At the time of the move to BP, the number of cryptanalysts had grown to around eighty-five and support staff had also increased, with staff numbers totalling around 200. In anticipation of the move, AGD wrote to all his staff on 11 July:

The War Station is to be manned from 15th August, unless otherwise ordered, in order to carry out a test mobilisation and to test war communications. Combined Navy and Air Force exercises are to take place from 15th to 21st August in which G.C.&C.S. may possibly take part.

Detailed orders for the move of the first wave will be issued later.

Leave arrangements are not to be interfered with. Heads of Sections should inform Commander Travis by 1st August which members of their sections will be on leave in order to assist the billeting and catering department.

With regard to railway fares, petrol allowances and subsistence allowances, the position should be cleared up now with the various departments concerned. It is to be hoped that similar arrangements to those of September 1938 should obtain, namely, Departments to pay full subsistence rates and the staff, being in receipt of lodging and food, should pay over two-thirds and retain one-third with a maximum of 5/- a day.

Mr. Clarke should clear up this question for Naval officers, Captain Tiltman for Military officers, Mr. Cooper for RAF officers and Commander Travis for members of the Foreign Office.1

He sent a further communication the following day:

In order to carry out communication tests the war site will be manned a.m. and p.m. 15th August by those detailed in G.C. & C. S. 1st wave who are not on leave at the time.

[Follows with instructions for those travelling by train or car.]

There will be no travelling allowances for those who do not make use of billets.

The official address for letters will be Room 47 Foreign Office and the telephone No. Whitehall 7947 but no private message is to be made from B. without authority.

The staff are warned against any conversations regarding the work with other members of the staff whilst in their billets. If occasion should arise as to what you are doing the answer should be that you are part of the aerial defence of London.

All leave was cancelled and Travis led the first wave of around seventyfour staff to BP and was in charge. He was joined by many of the Section Heads including Clarke (Naval), Miss Milne (Spanish Naval), O’Callaghan (Italian Intelligence), Craufurd (German Intelligence), Westall (Call Signs and Movements), Tiltman (Military), Jacobs (Italian), Cooper (Air) and Knox (Research). AGD himself led the second wave of around thirty-three staff a week later, along with some late arrivals. Hotels in Leighton Buzzard, Bletchley, Bedford, Buckingham and Newport Pagnell were used for accommodation, and there were separate lists for men and women.

Office space was limited at BP and AGD and his section heads were assigned rooms in the old house on the site. AGD’s office was on the ground floor in what had been the pre-war owner’s morning room. Here, he would personally welcome new staff members when they reported for work. AGD decided that it was time to strengthen the organisation by recruiting the men who had agreed the previous year to undertake secret work for the Foreign Office in the event of war. On 3 September 1939, AGD informed T.J. Wilson of the Foreign Office that they had been obliged to recruit men from the emergency list at the rate of pay agreed by the Treasury:

For some days now we have been obliged to recruit from our emergency list men of the Professor type who the Treasury agreed to pay at the rate of £600 a year. I attached herewith a list of these gentleman already called up together with the dates of their joining.

I will keep you informed at intervals of further recruitment.’2

The first intake arrived between 15 August and 2 September and included R. Bacon, L.W. Forster, Professor G. Waterhouse, Professor W.H. Bruford, N. de Grey, R. Gore Brown, Professor E.R. Vincent, Professor R.J.H. Jenkins and Professor T.S.R. Boase. On 7 September, AGD wrote to Wilson again with a list of the second intake, which included A.T. Hatto, Professor F. Norman, J.R.F. Jeffries, W.G. Welchman, Professor F.E. Adcock, Professor A.H. Campbell, Professor H.M. Last, A.M. Turing, F.L. Birch and Admiral H.W.W. Hope. They arrived between 4 and 6 September. Finally, L.P. Wilkinson and E.J. Passant arrived on 18 September. These twenty-one ‘men of the Professor type’ formed the vanguard of the vast expansion of GC&CS staff which would follow. Six of them had worked in Room 40, and only three, Jeffries, Turing and Welchman, were mathematicians. Six of the men were linguists, four were historians and eleven were or would become professors.

AGD had organised a short course in London from 3 to 6 January 1939 which was attended by M.P. Charlesworth, P.E. Charvet, D.W. Lucas, L.P. Wilkinson, A.M. Turing, H.M. Last, G.R. Driver, T.F. Higham and C.H. Roberts. Further recruits were put through a course from 20 to 23 March and from 27 to 30 March 1939. They were all earmarked for specific sections at BP on mobilisation and AGD gave a short historical sketch at the beginning of each course.

As more staff began to arrive, the logistical problems which had been identified during the ‘dress rehearsal’ the previous year, had still not been resolved. AGD wrote to Menzies on 12 September 1939:

My dear Menzies,

I am sending you herewith a memorandum which Travis and I have drafted as I had the Admiral’s permission to discuss administrative details with you. The whole question will shortly become so acute that it will have to be laid before him for decision, but in the meantime I wish to make you fully aware of the present position and of future requirements.

In addition to the present policy which has forced G.C. and C.S. into disintegration which I have always held to lead to a real loss of efficiency, I take the opportunity of repeating to you the discontent, in the staff of G.C. and C.S. which is now becoming increasingly vocal, with the actual conditions of work.

The contention is that G.C. and C.S., a Civil Service organisation, was moved out of London by orders of the Admiral and not by orders of the Foreign Office (our administrative head) and that therefore the G.C. and C.S. must receive equality of treatment with S.I.S. who were also moved by the Admiral’s order.

Travis and myself and the Senior Assistants now occupy fairly senior positions in the Service and many of our recruits are men of considerable distinction and it is definitely felt that in the allocation of accommodation such facts should be taken into account. It appears to me improper to invite such as these to try to do work requiring a high degree of concentration in overcrowded rooms.

Again the question of billeting, which Captain Ridley has carried out with such tact in the face of difficulty, has forced the staff to live many miles from their work and the question of transport is involved. It is felt that official cars can be made available for members of S.I.S. but G.C. and C.S. has had to raise a force of volunteers from among its own members and ask them to give their time and their cars to help their colleagues. In fine weather it is hard for a man who has had a heavy day to forego his leisure for this – in the dark evenings to come it will be even harder. If there are not sufficient official cars to do this duty would it not be possible to engage the W.V.S. to deal with the transport of the staff between office and billets?

I have done a great deal and will do all I can to maintain a spirit of cooperation. But there is a real spirit of discontent growing among my colleagues. I have congratulated them on the good work that is being done under very trying conditions and the natural reply is improve our conditions and you will get more results.

The few days that have elapsed since the outbreak of war are sufficient to show that we may hope very soon to contribute intelligence of a definite military value to the Fighting Services. If however we are to function efficiently we must be reasonably housed. These are the main considerations.

Cooperation between the three Service Sections is essential.

All sections should be in close proximity to the Teleprinter Room, for a great part of the raw material used by all sections is transmitted from the Y stations and some of the Cable offices. It should be remembered that The Foreign Office agreed to spend £4000 a month to ensure this rapid means of communication for its own ultimate advantage.

I have always viewed with very grave concern the fact that the Military Section has been moved to the garden to make room for a mess which is used for one hour per day, and the Air Section is also being moved away from the teleprinters to make way for a registry. The Air Section should be right on top of the teleprinters and the Naval Section, with whom it may have to confer urgently and frequently.

The Section working on the machine problem is in No. 3 Cottage and development there is becoming much more hopeful and here again they require very close cooperation with the section with whom they are working. The Diplomatic and Commercial Sections are in Elmers3 School. Although these sections are called Diplomatic certain of them require collaboration with the Service sections and produce matter of military importance. Twenty minutes spent walking backwards and forwards on a dark winter’s afternoon is not going to make for efficiency.

Further, the Naval Section is now grossly overcrowded and we have to remember that we have added to our staff volunteers of very considerable standing and the research work they will undertake is of extreme national importance and one which calls for some degree of comfort in their surroundings in order to get the best out of them.

It must be remembered that the three weeks we have been here have been remarkably fine and the walking about has been pleasant. With dark afternoons and evenings and cold conditions, people will hesitate to walk out in the open considerable distances to confer with colleagues. In our overcrowded state the use of the telephone, never satisfactory, is impossible.

It seems that there is not room to house SIS and GC&CS in Bletchley Park efficiently. The only alternative therefore is to separate. It appears to be most difficult to move the teleprinters and provide lines for them, and it therefore remains to examine whether alternative accommodation can be found for some or all sections of SIS.4

On 14 September AGD received a reply from Sinclair:

Colonel Menzies has reported to me the results of his interview with yourself and Travis, yesterday. I understand that some temporary arrangement of erecting further huts is contemplated, which it seems to me will not meet the case.

Now that the dug-out in the basement of Broadway Buildings is approaching completion, which will accommodate up to 500 people, is there any reason why the Diplomatic Section and the Commercial Section (2nd Wave) should not return to Broadway Buildings, so that the situation at the War Station, which I understand you describe as unbearable, may be relieved?

If you concur that this is desirable, in the interests of efficiency, arrangements should be made for the Second Wave to return to Broadway Buildings as soon as conveniently possible. If, however, you do not concur, I shall require from you the fullest and most convincing reasons as to why this should not be done.

Pending an immediate reply from you, I shall not give orders in regard to this matter. I understand that, in any case, the teleprinters will not be required to be transferred from the War Station, as I have gone very carefully into this matter, and I find that the material can be obtained direct from the Censors and Cable & Wireless.

Sinclair wrote again to AGD the following day after consulting with the DNI:

It is quite apparent to me that the Commercial Section of the G.C. & C.S. will require large additions to the staff, in order to enable it to cope with the work with which it is confronted.

As it is quite impossible to accommodate such individuals at Bletchley, arrangements should be made for the early return of the whole of this Section to London, in order that the work may be properly dealt with.

AGD had always believed that all of GC&CS should remain at BP and he made his case most strenuously in a note to Sinclair on 16 September:

In my private letter to Menzies I did not describe the position as unbearable and I was careful to raise in the annex only matters affecting the efficiency of the Service Sections. The transfer of the Diplomatic Sections to Broadway would not affect this problem, nor would it be possible to separate the Service Sections by housing one of them in the School.

Although I have no doubt that our personal safety would not suffer by return to Broadway, and personally I should much prefer to be near my home, I do feel that that the possibility of hours spent on a crowded public shelter and the time wasted in putting work away and getting it out again would render any real work by the Diplomatic and Commercial Sections quite impossible.

Suburban rail and road transport is difficult at present and it may become considerably worse, in which case it will be extremely difficult to put in a full day’s work.

The work of the G.C. & C.S. as a whole is bound to suffer if we are split into two sections e.g. as a first step in the coordination of the scrutiny of the mass of German traffic from all sources I have established under my own control a central German Coordination Section and would be difficult to determine whether this should be in Broadway or Bletchley.

My submission therefore is that the whole of the G.C. & C.S. including the Commercial Section should remain at Bletchley.

Captain Ridley is now arranging to remove the private furniture from the school and to have the lighting and heating put in order, when this has been done the working conditions in the school will be greatly improved. The large schoolroom is at present practically empty and I propose to transfer the Commercial Section there; it will accommodate about 30. If and when it were found necessary to expand this Section further, it should be possible to transfer the staff engaged on decoding legible commercial codes to a place near M.E.W.

There has been no question of the erection of huts for the Diplomatic and Commercial Sections.

There is now under consideration a plan for the erection of huts just outside the grounds of BP to house the Service Sections including their necessary expansion, thereby facilitating the necessary expansion of various sections of SIS. It would be necessary to connect these huts with the Teleprinter Room by pneumatic tube.

Finally I shall be personally very greatly relieved when these administrative difficulties are settled as I am most anxious to take my share of the work on the increasing numbers of cryptographic problems confronting us.

Crucially, for the ultimate success of BP, AGD won the day and by 29 September 1939, the huts were under construction.

AGD had kept in contact with Bertrand and in September, a party of French intelligence officers including Bertrand and Henri Braquenie visited BP. Knox was tasked with looking after them, and true to form, was soon writing to AGD about the matter:

My dear Denniston,

I think it is time we settled on one or two points of general principle.

Entertainment. It has been a great pleasure to me, though somewhat testing to my knowledge of French, to bear-lead Captain B. from 8 a.m. to 10 p.m. I have taken the line, though he offered to pay generously, that entertainment is une affaire de bureau: that is, from my angle, that I should get a billeting allowance from you or Ridley and that you or he should deal with the French. Drinks and transport other than that to or from the Office (for which I get an allowance) I treat as private liability. I trust that this view has been right and will continue, since I don’t like making special charges.

Machinery material and Statistics (Liaison).

We can also continue to cooperate on the reconstruction of the two Italian codes. As yet, there has been no discussion on Italian naval and military cyphers and on this question I should like to receive orders in view of the fact (a) that I suspect that the Italian Navy is being worked in another branch in Paris, and (b) that the Foreign Office considered that cooperation on the Italian military telegrams between Spain and Rome was, at that time, undesirable. I assume that Commander Travis handles any questions of finance arising from price of machinery or material (paper for ‘Netz (Filets)’ or wood or cardboard for rods).

Statistics. (Up to present). I take it that we have been making statistics at our own expense and Travis charges the material to the French.

As regards labour, then we should keep a check, if at all, only on time spent in reduplication which may be considerable as we may have to mark, punch and cut holes twice. It is easy to keep a check on time spent in this way. The French would get their stuff at about a quarter of what we would pay. I don’t see how they can actively help as they are a very long time behind and we should have to fly over heavy machines and quantities of paper, or, if they did help, risk everything being out of gauge.

At present I am talking only of Jeffrey’s ‘Netz (filets)’, (reduplication will begin in a few days), where I made some rather conditional offers, without, of course, mentioning finance. I think, however, we could only charge here for reduplication.

In the matter of sex-statistics there is no precise arrangement as yet either as to methods of as to finance, since all progress has been made since B’s departure (see my letter of the 26th Sept.). If my estimate of my new machine with Travis’s and H.-M’s improvements is correct we could either:

handle the whole affair on a fifty-fifty basis, or

Charge for necessary reduplications as suggested for Jeffrey’s ‘Netz (Filets)’.

If you can give any definite ruling as to whether:

We make no charge for labour.

We charge only for extra labour of reduplication.

We charge fifty-fifty.

I will institute a simple system of checking if necessary.5

On 4 September, two Cambridge mathematicians who were on AGD’s list arrived at BP and would prove to be fundamental to its ultimate success; Alan Turing, aged 27, from Kings College, and Gordon Welchman, aged 33, from Sydney Sussex. Both were greeted separately by AGD and then told to report to Knox, who had moved along with his small team into one of three cottages in the stableyard behind the house. Knox already knew Turing, as he had done some part-time work for GC&CS in 1938. Welchman had attended the courses in London in March but would later write that he had no recollection of meeting Knox at that time. While Turing remained in ‘The Cottage’ with Knox, Welchman was moved to the former Elmers School. It lay outside of the grounds of BP and had been acquired by GC&CS to provide additional office accommodation. While primarily tasked with analysing specific information included in every Enigma encrypted message,6 Welchman had other ideas forming in his mind.

When AGD and Edward Travis came together in 1919 in the newlyformed GC&CS, AGD had taken responsibility for cipher breaking, and Travis for cipher security under him. This separation of roles continued in the early days at BP, even though the cipher ‘Construction Section’ was now based in Oxford. Travis had been made responsible for the Service Sections of GC&CS in 1938. AGD was very busy coping with the administrative problems arising from the move to Bletchley and the subsequent expansion and as a result did not spend much time out of his office. Travis did make it a habit to get out of the office to see the work on the ground and talk to the staff. So Travis was in effect responsible for the ‘Enigma Section’, though Dilly often continued to write straight to AGD. Travis also had a direct interest in the security of Enigma as at this time he was concerned with the deployment in the British Services of the Typex machine, which was designed on very similar lines.

Working away in Elmers School with another member of Knox’s team, Tony Kendrick, Welchman was seeing something in the intercepted traffic which had escaped others. As he later recalled:

Previously I suppose I had absorbed the common view that Cryptanalysis was a matter of dealing with individual messages of solving intricate puzzles and of working in a secluded back room, with little contact with the outside world. As I studied the first collection of decodes, however, I began to see, somewhat dimly, that I was involved in something very different. We were dealing with an entire communications system that would serve the needs of the German ground and air forces. The call signs came alive as representing elements of those forces, whose commanders at various echelons would have to send messages to each other. The use of different keys7 for different purposes, which was known to be the reason for the discriminants, suggested different command structures for the various aspects of military operations.8

While analysis of the enemy’s wireless traffic was undertaken both by Room 40 and MI1(b) during WW1, what no one at BP seemed to have recognised was that a considerable amount of intelligence could be obtained from intercepted German messages by analysing the traffic as a whole. Welchman drew up a comprehensive plan calling for the close coordination of radio interception, analysis of the intercepted traffic, breaking Enigma keys, decrypting messages on the broken keys and extracting intelligence from the decrypts. It is likely that as Travis was a more visible presence at BP in the early days, Welchman decided to present his plan to him and he immediately saw the urgent need to act on it. Welchman convinced Travis that a large scaling-up of the effort would be needed when the methods of breaking Enigma, outlined in his plan, produced results. He was in effect proposing a system of mass production which was completely at odds with the approach taken by Knox. In his world, the various tasks of decryption, translation and writing the resulting out-going message were all performed essentially by one cryptanalyst. Welchman and now Travis realised that this approach would simply not be able to handle the volumes of intercepted traffic envisaged. It would have to be replaced by a clear division of labour amongst a team of experts. Travis won AGD over to the idea and then remarkably, persuaded Whitehall to back this gamble, even though not one German Enigma message had ever been broken in the UK either before or since the war began.

Welchman’s plan was soon the subject of discussion around BP and not surprisingly, Knox was not happy with it. His view was that research was all important and that ‘Bletchley Park should be a cryptographical bureau supplying its results straight and unadorned to Intelligence Sections at the various Ministries. At present we are encumbered with “Intelligence Officers” who maul and conceal our results, yet make no effort to check up on their arbitrary corrections.’

He was questioning the whole intelligence distribution chain which was being proposed for BP. The following letters reveal Knox’s views and AGD’s patient attempt to explain the rationale for Welchman’s plan.9

On 6 October 1940, Knox wrote:

My dear Denniston,

This Italian business has now diverted large proportions & takes almost all our time in the cottage & very much work is done in the hut. While I expressed myself willing to decode occasionally for the Naval Section, I am bound now to raise the question of circulation. Apart from consideration of our position – why should the largest & most important section not use its own existing mouthpiece? – the Enigma results are of an order of certainty differing wholly from the products of most other intelligence sections.

On personal grounds I find that I have been ?? to our arrangement of Dec 5th etc. Had I appreciated at the time the sense in which you now take it – I should have gone to any lengths to oppose it.

I must ask you to deal at once with the question. I have no intention of continuing to work as an obscure subordinate of Commander Clarke.

Yours faithfully

A.D. Knox

On 8 October 1940, AGD replied:

My dear Knox,

Here is my view of what happened. If there are any discrepancies – we can clear them up.

The meeting of December 5th decided on the division of Enigma work into Research and Production. When on January 24th the first current solution was obtained the section known as FJ (now Hut 3) was formed to translate and circulate this traffic and to study. It accepted the cover of S.I.S. and all results are attributed to Secret Service reports. That is the existing mouthpiece of the German Air–Army Enigma.

When in January the solution of the Spanish Naval Attaché Enigma messages was obtained, circulation was controlled and continues to be controlled by the Spanish Naval Section.

When the research party broke into the Naval Enigma for certain days in April, the circulation of results was made through the German naval section.

When the machine used by the German Railways was fixed early in August results were circulated from the military section.

If, as I hope, you obtain the solution of the machine used by the German Secret Service I anticipate that Strachey’s section will handle the circulation, as they have already dealt with so much traffic in other cyphers.

As far as the Italian Naval Enigma is concerned (the subject of your letter), I cannot understand why you should wish for an alteration of the practice.

Clarke deals with the circulation of all this traffic of which the Enigma forms a part. He dealt with it pre-war days when you first broke into the machine.

If the duty were given to Hut 3 it would be necessary to find Italian speaking staff to work there and to study the contents, in fact to duplicate the work which Clark’s section already does.

So far as the personal side is concerned I hope you do not underrate your own position. From the above it is obvious that the Research side of Enigma, which you direct, has met with very considerable success and it must be perfectly clear to you, to all those concerned in G.C. & C.S. and to the recipients of the decodes that without the Cottage and Huts 6 and 8 there would be no enigma traffic.

That is my view: I cannot, therefore, see any reason why the existing methods of circulation should be changed.

AGD had always had a cordial working relationship with Sinclair, who as DNI had been part of the Committee which had appointed AGD to his post. Sinclair had been suffering from cancer of the spleen and was taken to hospital in late October 1939. Characteristically, he sent a message to a friend on the morning of 4 November saying ‘First bulletin: Nearly dead’. He died at 4.30 pm on the same day. Stewart Menzies was Sinclair’s deputy and the day after Sinclair died, he gave Lord Cadogan, Permanent Under-Secretary for Foreign Affairs, a sealed letter written by Sinclair two days earlier. In it Sinclair strongly recommended that Menzies should succeed him.10 After a delay of three weeks, Cadogan noted in his diary on 27 November: ‘Tiresome letter from Menzies, with whom I sympathise. Am trying to binge up H. [Lord Halifax] to get decision [on Sinclair’s successor] tomorrow. M. [Menzies] is in a difficult position, and it’s silly of everyone to go on funking Winston.’

It seems that Churchill favoured Admiral John Godfrey, who had succeeded Sinclair as DNI. However, he had been a battleship admiral and only had some ten months in the intelligence service. The following day, at a meeting attended by the Prime Minister and the service ministers, Cadogan wrote that Lord Halifax ‘played his hand well and won the trick’. It was unanimously agreed that Menzies should have the job and on the 29th, Halifax duly offered it to him. There was a caveat that there should be ‘some enquiry’ into the organisation of the Service.11

On 18 November 1939, AGD received the following memo:

Commander Denniston.

Now that we may with some hope look forward to the state when we shall be able to deal with some of the German Enigma traffic, I think we must consider how best the traffic could be deciphered with the minimum loss of time.

If conditions remain as at present, I understand the position to be such that when the ‘Netz’ are complete we shall be able to decipher traffic from several groups which use the Standard Indicating System. When this becomes a fact I should like to see Research divorced from Production and the work organised on the following lines:

Research Section who should investigate the still unknown problems such as the Naval and T.G.D. This should be done by Knox, Kendrick, Turing, Miss Nugent, and such of the clerks as Knox requires.

The production section requires dividing into several subsections as follows:-

Receiving, Registration, sorting and W/T Liaison. This section would prepare data for Netz and Bombes. Staff: Welchman, Twinn and 4 clerks.

‘Netz’ party. The work of finding machine settings etc., from sheets punched from cyclometer results, Jeffries + X assistants

‘Bombes’ machines run by Dawson + 1 assistant.

Decyphering Section. This should include staff to test ‘Netz’ and ‘Bombes’ results. They will decipher all available traffic with minimum loss of time and pass to Service Sections for translation. It will require someone (or ones) with good German to scrutinise traffic before passing on for translation. Two female clerks must be trained by R.A.F. to work their machines.

A special hut will be required for the Production section.12

The memo itself is not signed and was certainly not written by Welchman, as he would never have proposed himself for any specific role. At the top right of the front page of the memo are the words ‘Paper? By EWT’. It is highly unlikely that Travis would have used the words ‘I should like to see’ to his superior. In all likelihood, it was written by Menzies who was already making his mark on part of his new organisation. It was clearly based on the Welchman proposal13 for an organisation which would remain basically unchanged throughout the war, with the hut numbers becoming, in effect, the cover name for their activities. The new Production section initially set up shop in the Elmers School and by late January 1940, two new wooden huts were ready for occupation. The Production section moved into Hut 6 and soon became known by that name. The linguists and intelligence officers who would translate and interpret their output moved into the adjacent Hut 3 and soon adopted that as their section name. Their naval counterparts would eventually be housed in Huts 8 and 4. Travis continued to take direct responsibility for the Enigma huts as they came on stream, their staff and the mechanisation programme.

The ‘Menzies memo’ can be seen as a direct challenge to AGD and his position as Head of GC&CS. He was very much Hall and the Admiralty’s man when he took up his post at the end of WW1. He maintained an excellent working relationship with Sinclair but his relationship with Menzies was less certain. Menzies was, after all, an Army man and Hay, the Army’s candidate to be Head of GC&CS, had been overlooked in favour of AGD. However, there is no evidence that Menzies was party to the process which saw AGD chosen over Hay. Perhaps AGD’s letter to Menzies on 12 September, describing all of the administrative difficulties at BP had planted in Menzies’s mind, seeds of doubt about AGD’s managerial competence.

***

Both Turing and Welchman had started to think about how machines could help with the work soon after their arrival at BP. First Travis and then AGD had been won over to the potential of machines to speed up the decryption process. Turing’s work on a machine solution had reached the build stage by the autumn of 1939 and the British Tabulating Machine Company at Letchworth had been contracted to carry out the work. Their Research Director, Harold ‘Doc’ Keen needed to be briefed on BP’s requirements and one of Knox’s team, Peter Twinn, was given the task.14 By March 1940, the manufacture of the prototype Bombe, a complex electro-mechanical machine, was well under way. The first prototype, named Victory, was installed in Hut 1 on 18 March but did not prove particularly effective. It was only when a second and improved machine was installed in Hut 1 in August that real results were achieved. This machine, named Agnus, incorporated a brilliant design modification invented by Welchman and called the Diagonal Board. Victory was then moved to Wavendon as a training machine, as it was unreliable and six more machines were on order by November. The first of the even more sophisticated models, the Jumbo Bombe, arrived in Hut 11 in March 1941.

Recruitment started almost immediately for the high-quality staff that would be needed after the emergency list that AGD had drawn up the year before was quickly exhausted. A new intake was needed as soon as possible. Welchman returned to Cambridge and began recruiting former colleagues and students, while Travis recruited from the commercial world. A number of young and intelligent women were brought into the fledgling Hut 6. With recruitment came administration to support it and on 10 November, 1939, AGD issued a notice that ‘In future Paymaster A.N. Bradshaw R.N. will act as General Administrative Officer for the G.C. & C.S. and all questions in this connection should be referred to him.’15 On 8 October 1940, AGD informed staff of further changes in the administration of BP: ‘By direction of the CSS, the general administration of the War Station B.P. will in future be under the joint management of Captain Ridley R.N. and Paymaster Commander Bradshaw R.N. who will form a Joint Management Committee (short title J.M.C.).’

During 1940 and 1941 this committee issued notices on subjects such as catering, billeting, addresses, personal security, maintenance/repairs and appointment of administrative sub-sections. It was abolished on 12 May 1941 after the Joint Committee of Control (JCC) was set up in April. It was chaired by the Deputy Chief of the Secret Service (Valentine Vivian) and included Travis, Tiltman, Bradshaw, Earnshaw-Smith, Hope, Cooper, Ridley, Hastings and Woodfield. At its meeting of 5 April 1941, it dealt with the future of Elmers School, catering and the BP recreational club and tennis courts. On 12 April they agreed to recommend building a dining hall with provision for serving 1,000 at each meal. It was agreed to take over extra land if suitable.

Knox continued to be a thorn in AGD’s side and usually included a threat of resignation along with his latest complaint. He wrote to AGD on 7 January 1940,16 reminding him that ‘on our journey to Warsaw I promised to assist the Poles and the French in producing statistics’. This had not been done and Knox went on to say, ‘My personal feelings on this matter are so strong that unless they leave by Wednesday night I shall tender my resignation.’ Surprisingly, given that Knox was supposed to be at the heart of the Enigma work, he closes with: ‘I do not want to go to Paris but if you cannot secure another messenger I am actually at the moment completely idle.’ In the end Turing was sent to Paris to meet the Poles. On 9 January 1940, unknown to Knox, AGD wrote to Menzies with regards to the Poles:

Dear Menzies,

Here are the names of the three young Poles, Jerzy Różycki, Marian Rejewski, Hendryk Zygalski.

If we are faced with a change on the outbreak of war (and we begin to suspect it), the experience of these men may shorten our task by months.

We possess certain mechanical devices which cannot be transferred to France. These young men possess ten years’ experience and a short visit from them might prove of very great value.17

On 10 January, AGD wrote to Rivet, Bertrand’s superior, urging him to allow the three Poles to visit Britain for a short period. They were at that time working at a joint French/Polish intelligence station near Paris called PC Bruno, and the request was denied by the French.

AGD’s workload was increasing dramatically and not only was he dealing directly with the three Service Ministries, he was also in regular contact with intelligence chiefs, as the following memo from DNI John Godfrey, sent on 31 October, reveals:

Clarke has been complaining about delays in sending naval intelligence out to Commanders-in-Chief. He understands that the R.A.F. Section transmit direct to Cairo without reference to the Air Ministry using the R.A.F. High Speed W/T Service. This may be the origin of Clarke’s complaint.

He goes on to say that the Chiefs of Staff are instructing the three Commanders-in-Chief to set up a Combined Bureau under Jacob.

He also says ‘I am going into the question of setting up an organisation to arrange “pinches”, and I think the solution will be found in a combined committee of talent in your department and mine, who can think out cunning schemes.’ 18

On 9 April 1940, the so-called ‘Phoney War’19 ended when Germany invaded Denmark and then Holland on 10 May. A new Enigma military key appeared on 10 April for operational traffic involving all three German services. It was broken daily by Hut 6 from 15 April and as the workload increased, Hut 3 moved to a three-shift system. Intelligence reports, disguised as agents’ reports, were passed to the War Office and Air Ministry and they in turn communicated the information in secrecy to commands in Norway. The Admiralty also had a communication channel in place and had been informed as early as 5 January that messages prefixed ‘HYDRO’ would contain information ‘from a very authentic and secret source’. On 15 May, the prefix was changed to ‘ULTRA’.20 Hut 6 had decided to concentrate its limited resources on the general-purpose ‘Red’ key of the GAF although there was an increasing amount of military traffic. In early May, the Germans changed the Enigma indicator system that the Poles had exploited21 which meant that no breaks were made again until 22 May. From that point on, success was continuous as traffic increased to 1,000 messages per day. However, the Service channels were by now completely disrupted and by 24 May only one link remained, a SIS mobile unit attached to GHQ

Unfortunately, the Sigint intelligence proved to be of little tactical value at this stage for several reasons. Hut 3 lacked experience and the reference books and maps necessary to assess the information were unavailable. Ministries found it difficult to assess its significance and commanders in the field could only take the intelligence at face value as agents’ reports. Furthermore, the intelligence reports frequently arrived too late for action to be taken. Finally, there was no real military capability in the field to act on it in an effective way. GC&CS had, however, put in place a secure method of distributing intelligence to GHQ in France. Signals were typed and then checked by the No. 5 of the Hut 3 Watch.22 One copy was passed to the SIS Codes Section in BP where the message was encrypted with an OTP. This version was taken by despatch rider to Section VIII at Whaddon23 for transmission over the SIS W/T channel to the SIS representative in France for decrypting into plain text before delivery to GHQ.

By April 1940, GC&CS’s Naval Section had built up a fairly complete picture of the German W/T organisation as part of its work on traffic analysis in support of cryptanalysis. From the beginning of 1940, short reports of operational interest were flowing via teleprinter from German Naval Section to the Admiralty. Some senior staff seemed to resent this intrusion on their ‘patch’ and thus, at its prompting, the Operational Intelligence Centre (OIC) was sceptical. The sinking of the aircraft carrier HMS Glorious off Namsos by Scharnhorst and Gneisenau on 8 June was a turning point in the OIC view of GC&CS intelligence, as they had ignored several weeks of warnings from GC&CS. The War Office and Air Ministry also showed an increasing confidence in the work of AGD’s organisation by placing officers in Hut 3. By the summer of 1940, the RAF intercept station at Chatham started its move to Chicksands.

Thanks in part to intelligence from BP, the British Government realised that the British Expeditionary Force in Europe was in a hopeless position. From 27 May until 4 June, some 338,000 men, of whom 224,000 were British troops, were rescued from the beaches of Dunkirk. The evacuation of Norway was completed by 8 June and on 10 June Italy declared war against France and Great Britain. German Panzer divisions quickly moved across France and the country was forced to surrender on 22 June.

Given that Britain now stood alone and invasion was a real possibility, AGD put together a plan to ensure that his organisation could continue to operate if Britain was overrun. On 26 June 1940, he wrote to Menzies with the details:

I attach a plan for the disposal of our records and would be glad to know which items of this plan you would sanction in order that I may take early action. My plan does entail certain risks, though risks may have to be taken at this stage. I have not mentioned a more far reaching suggestion namely to contemplate sending skeleton crews of certain Diplomatic Sections to Canada. The difficulty would be that we would obtain very little material and I doubt whether at this stage such a plan would do more than attempt to preserve continuity for a post war era.

DISPOSAL OF RECORDS

To Canada via D.M. and D.N.I. Ottawa.

Office personal records.

CXFJ records of 1940.

Plans of main machines.

One E machine.

Lloyds Bank Dunstable.

Office personal records.

Copies of main important books.

Sectional records

This because when all is over (a) either we have won or (b) we are defeated.

If (a) we may want to begin again.

If (b) a compromise of our activities will not surprise the victors, should they discover these papers.

In this respect, I blame myself alone for destruction of French naval records which might have been of use today.

Certain Diplomatic sections may be invaluable during negotiations viz. American, S. American, Spanish, Vatican, Turkish, Arabic, Persian, Chinese & Japanese.

If I can disperse these sections in a crisis in the case of trustworthy leaders to unobtrusive unknown private homes with a promise of destruction in the face of danger, these sections could be reassembled and made to function at short notice should it be necessary and should material again become available.

Thus, for example, the American section (Captain Hanly and Miss Curtis) have a little villa in Water Eaton. They could here keep current books and material and rejoin; the Chinese section leader, Colonel Jeffrey, is with Sir Everard Duncombe at Great Brickhill with cellars and security and obviously a country gentleman and nothing more.

Similarly I might find safe homes for the other important sections. Some risk must be accepted. If we are defeated, what extra harm will be done, if we win we keep the stuff in odd places and start again when we are wanted.24

By September 1940, BP’s codebreaking efforts were starting to have real impact on the conduct of the war. Hut 6 broke a key which they called Brown I and was used by the GAF Signals Experimental Regiment.25 An earlier decrypt on 5 June revealed that something called ‘Knickebein’ was being used by German aircraft with special receiving equipment. It was already known that this was the cover name for navigational beams. No.8 Group (Bomber Command) was formed and became responsible for all radio countermeasures. By October, their success forced the Germans to switch to another system, the ‘X Gerãt’, used by the pathfinders of KG 100 to locate and illuminate targets for the main bomber force. Hut 6’s break of Brown I allowed the X Gerãt transmissions to be jammed by the end of 1940. Good liaison was established between Huts 6 and 3 and Assistant Director of Intelligence (Science) in this work. As Birch wrote in his Official History after the war: ‘In 1940 we find only the beginnings of a long story of closely integrated cooperation between operators, log-readers, low and highgrade cryptanalysts, reporting staff and technical intelligence officers that lasted throughout the war and was unique of its kind in the history of British Sigint.’

***

To provide contingency against damage to the six fixed Y stations operational at Denmark Hill, Sandridge, Cheadle, Chatham, Flowerdown and Scarborough, Chicksands was selected as a suitable inter-service site and houses at Wavendon were acquired as a back-up to BP. In case of invasion, quarters were found for around 150 GC&CS staff near Market Drayton. The position by the end of September was grim, with buses providing transport not operable, incomplete billeting accommodation, intercept conditions dubious and a lack of an alternative site evident.26 AGD did not believe GC&CS could function if it had to move far from BP. By 13 September, German Naval Section inferred from traffic analysis that everything was in place for an invasion but on the 15th, the danger of immediate invasion had receded. This was confirmed from special intelligence at the end of October.

When Italy came into the war, GC&CS was better prepared because of its focus on Italy and Japan between the wars. However, from September 1940, the Italian components of the three service sections at BP struggled to maintain enough staff as many were seconded to locally-based units at Alexandria, Sarafand and Cairo. Some work in the field on Italian ciphers was supported by GC&CS and some at BP as research activity. Middle East military commands wanted more GC&CS staff, claiming that delays rendered its contribution ‘of academic interest only by the time it is received’.27 These claims were rejected by the heads of the Army and Air sections at BP, Tiltman and Cooper.28

The Italians had made changes to their high-level code books and ciphers in July and added new ones so that by the end of the year, a multiplicity of new ciphers caused a complete blackout. However, in September Knox broke an Italian machine which had been in use during the Spanish Civil War. While traffic was minimal, it included very important intelligence – most dramatically during the Battle of Matapan.29 Middle East Control was having success with the East African cipher, while GC&CS struggled against the main Mediterranean cipher which changed frequently. Thus Middle East control pressed for control over all Italian Sigint work. AGD, however, continued to argue for the model of research at home and exploitation in a combined Middle East bureau. A party from GC&CS consisting of one naval, three military, three RAF and two Foreign Office officials30 left England on 18 July, followed in August by the head of the Italian Military section, F.A. Jacob, and clerical staff. The intention was to set up an inter-service cryptanalytic centre. AGD reported that ‘it is not yet known where they will work in Cairo nor under whose organisation’.31 The three Directors of Intelligence agreed on 29 October that an inter-service cryptographic bureau should be set up under Jacob.32 The so-called W Committee in Cairo accepted the proposal with certain reservations, as the new Combined Bureau Middle East (CBME) was in effect a cryptanalytical bureau, not a Sigint centre. CBME was supposed to be an inter-service cryptanalytic section reporting to a W Committee. As AGD said ‘there is in effect as yet no real inter-service bureau but three components each taking orders from their own Service authorities, Jacob [Lt.-Col Jacob, Director CBME] being allowed to try to co-ordinate their work’.33

While the Italian Naval Signals Intelligence Section was making little progress, according to Clarke, Head of the Italian Naval Section at GC&CS,

it would be a mistake to bring Murray’s [Commander J. Murray, Head of SI] party home. Cryptography has its ups and downs, and a little luck might easily change the situation in a moment. The capture of documents might … create the necessity for a decoding staff there – there has never been a cryptographical staff. There are plenty of minor … jobs for them to tackle now – Fleet codes, reporting codes, mercantile codes, etc. Their efforts are wasted, if they try problems too hard for them.34

While AGD thought that the inter-service Sigint model should be followed in the Middle East, Birch argued in his Official History that while inter-service was a nice principle,

at GC&CS itself, although the Sigint work of all three Services was conducted in one place to very great mutual advantage, inter-service fusion of functioning was limited to the use of analytic machinery and to army-air partnership in the solution of and exploitation of German Army and Air Enigma traffic as a result of the originally fortuitous interception of the GAF traffic by a military Y station and the subsequent artificial segregation of this enterprise from all other Sigint activities, and of its subordination not to War Office and Air Ministry but to SIS.

As early as 1937, the cooperation of Commonwealth Allies had been sought to obtain traffic from commercial telegraphy stations. There was wireless intercept cooperation with the navies of Canada, Australia and New Zealand from around 1925, and DNI Ottawa’s station at Esquimalt, British Columbia became a useful source of commercial intercepts for GC&CS. As well as Esquimalt on the Pacific, Canadian naval Sigint had Y and direction finding stations at Hartlen Point, Nova Scotia, and St. Hubert, Quebec. Australia also wanted to help and considered it ‘desirable to examine the possibility of establishing a nucleus organisation in this country to guard against the contingency of operations in and about Australia and her territories’.35 However, little was achieved for some time. New Zealand established a ‘Combined Intelligence Bureau and Central War Room’ in Wellington in September, and exchanged information with FECB in Singapore. South Africa could do nothing officially for political reasons, but discretely, a chain of direction finding stations at Bloemfontein, Durban, Johannesburg, Komatipoort, Port Elizabeth and Simonstown proved valuable.

Other European allies emerged, and the Finnish General Staff offered cooperation with a GC&CS Russian Section and Tiltman obtained from them ‘information, copies of documents and intercepted material of very great value’.36 Just before the French campaign, French Navy and Army cryptanalysts were seconded to GC&CS. However, after the French armistice with Germany on 22 June 1940, they gradually left BP.37

Birch summed up the situation at BP at the end of 1940 as follows:

Dissected thus, G.C. & C.S. as a working organism appears freakish. Its administration was not made easier by the fact that Bletchley Park was at that time the ‘War Station’ of the S.I.S as well. In November 1939, Commander Denniston had appointed Paymaster-Commander A.R. Bradshaw, R.N. (retd.) as ‘General Administrative Officer for the G.C. & C.S.’ component but in October 1940 ‘by direction of the C.S.S., the general administration of the whole War Station was placed under a ‘Joint Management Committee’ (J.M.C.) consisting of Captain W.H.W. Ridley, R.N. (S.I.S.) and Paymaster-Commander A.R. Bradshaw (G.C. & C.S.). The dual control did not function very smoothly or efficiently, and, what with one thing and another, the administration both of work and for maintenance came in for a good deal of criticism.

The case for the defence is fairly obvious: It is easy to be wise after the event; in a succession of emergencies only hand-to-mouth empirical improvisations are possible. With so many Ministries fingering the pie, each proffering a different solution to every problem and demanding different treatment, no uniform pattern was possible. The unforeseeable contingencies of bombing and invasion made long-term and large scale planning impossible. In 16 months the nominal role of G.C. & C.S. had increased fourfold and, if working accommodation and billets were insufficient and bad, morale was never higher (civilian recruits had all volunteered, and war was not yet routine).

However, these weighty considerations do not entirely dispel the impression of a rudderless vessel buffeted about at the mercy of every wave of circumstance. On the one hand, there is considerable negative evidence of the lack of any adequate machinery for government; on the other hand, there seems to have been some confusion between administration in the sense of governing and administration in the sense of providing ancillary services; so that policy appears unduly conditioned to the convenience of the latter. Such, at all events, were the opinions formed, and expressed more bluntly, in the Service Ministries. Signs of a change of outlook on the part of the G.C. & C.S. management are, however, perceptible in a memorable ‘Introductory Remark’ to Commander Denniston’s ‘Report for 1940’ to the Director: ‘In the past we have fitted the work into the huts as they became available. I believe greater efficiency could be obtained by arranging the huts to suit the work.’

AGD’s end-of-year report to Menzies reveals just how busy his organisation had been:

Executive Summary:

I submit herewith a survey of the work of the G.C. & C.S. during 1940, and a report on the position of enemy and neutral ciphers at the beginning of 1941.

I have included a brief resume of the methods of circulation of results to the Departments concerned in case you may wish to make any alterations or expansion.

I have also given details of the staff at present employed on the work, with the estimate from Heads of Sections of necessary increases during 1941.

I have had to ask your sanction for increase of accommodation at the Park during 1940, and it is only my duty to keep you informed of any possible further demands which may have to be made during the coming year.

The increase of staff to meet increase of traffic, and success in tackling new problems, is very closely connected with office accommodation, billeting and transport.

I would suggest that any further building be based on a longterm plan rather than hut-building to accommodate new sections.

In the past we have fitted the work into the huts as they became available. I believe greater efficiency could be obtained by arranging the huts to suit the work.

The ideal (which we can now not attain) would be a star-shaped conclave (to permit expansion) with a D & R (Distribution & Routing) and Teleprinter room in the centre, all interconnects with pneumatic tubes.

The saving of time and staff would well have justified a high initial expenditure.

From the purely cryptographic side of the report certain facts emerge very quickly:

Germans and Russians have taken steps that their diplomatic cyphers shall not be read.

Both these powers have had ample warnings and have profited.

With the introduction, during 1940, of individual tables into our own F.O. service, I am satisfied that at last our own diplomatic authorities have adopted enemy methods and safeguarded our cypher communications.

From a perusal of the reports of our service sections, it seems clear to me that the Naval authorities of the Great Powers pay greater attention to cypher security than their sister services.

Although we employ a large staff of experts on German Naval and Italian Naval work, very few Naval cyphers have become legible since the entry into the war of these powers. French Naval cyphers are legible chiefly because of the capture of the French S/M Narval. We had, therefore, been forced in peace to study the new art of W/T Intelligence or Y Intelligence and to assist in its development. I do not, however, intend to include any notes on this subject in this cryptographic report.

The Far East and Near East, who had hoped perhaps that their security lay in language, have been obliged also to tighten up their cypher methods.

We are nearly keeping pace and obtaining solutions but it is only a matter of time until these Powers too produce methods which may make solution more difficult and irregular.

In 1935 I asked Commander Travis to investigate the possibilities of mechanical aids in our work. He started then, but only in 1940 was he able to achieve very considerable success, as is shown in his report.

I consider this success largely due to Travis’ intimate cooperation with B.T.M. who have given of their best in staff and equipment, and Travis has known how to utilise it. Thousands of hours and hundreds of staff have been saved by these efforts.

This success has forced us to modify our views on the safety of subtractor tables. Every service using general tables must provide an adequate supply to enable more frequent changes, and must institute safeguards against misuse and overuse of their tables.

Were it not for the loyal cooperation of Colonel Tiltman (Head of the Military Section) and Mr. Cooper (Head of the Air Section) I hardly know how this large interservice office could have been run. Tiltman and Cooper both owe loyalty to their Service chiefs. But they have never failed to back our main duty, attack on enemy cyphers. They are well aware that interservice cooperation as it pertains here is the only way of fulfilling the functions for which we are appointed.

Apart from the normal expansion in the various sections as detailed in this report, I have in mind the development, in which all my senior colleagues agree, of a Service Distribution and Reference office on the same lines as the Diplomatic D. and R. of which Smith is the Head.

Decodes of operational value will continue to be teleprinted direct by the Sections as at present. The distribution of typed copies would however be done by this new Section, who would also distribute them among the Sections here, and maintain all the information from this and other sources in a form for easy reference by the Sections.

If it were possible, this Section should be accommodated next to the Diplomatic D. and R.; but this cannot be so on account of our present accommodation.

The new Section must be in a central part of B/P, and I consider that the senior staff should consist of officers from the Intelligence Divisions of the three Services, who should know the requirements of the general staff and a member of G.C. & C.S. who should know the possibilities of cryptography and the needs of cryptographers. It is in no sense an Intelligence Office except in so far as the needs of the Service Sections of G.C. & C.S. require a centralised Intelligence and File of enemy telegrams which would assist their work.

This Section would have a threefold purpose:

It should be of great assistance to the cryptographers to have a central office to which they could refer for information which may help them in their own problems, or when they can search among contemporary decodes for cribs.

It will meet a need sometimes expressed by the Intelligence Department of the Services for a central office, where all decodes are available for scrutiny by a member of their own Department, and so provide against the loss of anything which might be of interest to them.

It will relieve from the cryptographic sections the responsibility for the distribution of decodes and thus give them more time for their production.38

AGD was also keen to establish with Menzies, as he had done with Sinclair, the importance of maintaining a unified cryptography centre as evidenced by this note from him to Menzies on 22 December 1940:

The Romer Committee in 1919 founded the G.C. & C.S. and directed that all cryptography should be centred there, the Army and Navy to collect the necessary W/T material, of which there was then very little. The G.C. & C.S. was also entrusted with the security of British Cyphers and their construction.

For the first few years W/T interception was kept going with some difficulty owing to the urgent necessity for economy. The R.A.F. came into the picture in 1927.

For cryptography, a military section was started in the G.C. & C.S. in 1932 [?] so that a party would be available for service in the field, and an Air Section was started in 1936. A Far East Joint Bureau was instituted at Hong Kong, administered by the Navy and the Head of the Bureau is paid for by the F.O. A Middle East Joint Bureau has only just come into being.

As you know the fighting services, especially the Army and Air, have been served with intelligence far beyond their expectations during operations in Norway and France and now at Home. The story of this is of some interest in pointing out the benefits of centralisation.

In 1939 (and for some years before) the Army at their Chatham Y Station were intercepting traffic from a very large group of stations in Germany, which were thought to be serving the German Army.

In January 1940, thanks mainly to the S.I.S. and their association with the G.C. & C.S. , this traffic became legible and turned out to be point to point station traffic of the German Air Force. From that moment until fairly recently the Army (MI8) have endeavoured to give up taking this traffic, well knowing that there is no one else to take it and despite the fact that during Spring and Summer it provided Army intelligence of the highest value in Norway and France, but because it emanated from the G.A.F. MI8 have tried to drop it.

The R.A.F. had always maintained that nothing of operational value would come out of point to point traffic and therefore, had made no plans for taking it and did not commence doing so until and are not even now in a position to take it over completely.

In April, it soon became apparent that the Army had insufficient sets and operators to cover the traffic satisfactorily and 18 sets were eventually diverted to this work at the Foreign Office Y stations at Sandridge and Denmark Hill, whose proper job is the interception of traffic in commercial routes. Without these additional sets much less of the intelligence would have been obtained.

I maintain, therefore, that if it had not been for our very close association with S.I.S. in the first place, and the fact that G.C. & C.S. were able to pool available W/T and cryptographic resources, much of this very valuable intelligence would have been lost and would not now be obtainable.

This example of the benefits of unification of cryptography in one centre is just additional argument to the many that can be advanced for the advantages cryptographers desire from working in the closest association.39

GC&CS continued to grow and by the beginning of 1941, numbers had more than trebled to around 685. The teams working on Enigma had also grown quickly and Huts 6 and 3, which worked on German Army and Air Force Enigma, had ninety-three and sixty staff respectively. Huts 8 and 4 worked on German Naval Enigma and had thirty-seven and forty staff respectively. Knox’s Research Section in The Cottage numbered nine staff! Responsibility for recruiting additional scientists and mathematicians was given to C.P. Snow of Christ’s College, Cambridge.

***

AGD had moved his family into Stapleford Mill Farm near Bletchley on 13 September 1939, and they would remain there for two years. His son Robin was sent to boarding school at Downsend School between Ashtead and Leatherhead. They regularly entertained friends and GC&CS colleagues and de Grey, Adcock and Birch were frequent visitors. The Dennistons would visit the Knoxs’ at their home at Courns Wood, a large ten-bedroom house set in ten acres of private woodland near High Wycombe. Dorothy got on well with Knox’s wife Olive but the two men were not close friends. Their battles over control of the Enigma problem at BP had no doubt taken its toll. De Grey would usually appear at Christmas with presents for Robin and ‘Y’. These would inevitably be tokens to buy framed Medici prints as he had run the Medici gallery before the war. AGD’s circle of friends included Rhoda Welsford whose mother rented Newton Longueville manor house, a mile from BP for the duration of the war. Rhoda worked in the Air Section from September 1939 until November 1944. Christmas 1940 found the family at the farm with a gardener and a cook. Christmas dinner was at the Welsfords at Newton Longueville. The Manor housed ‘the Profs’ – ERP Vincent, Frank Adcock, Tom Boase and Hugh Last from Kings, Magdalen and Brasenose respectively. All took part in paper games with the Denniston children. Tiltman was also a close friend of AGD, as were their respective wives. On 12 June 1941, AGD was appointed a Companion of the Order of St Michael and St George (CMG), as with his previous honour, in his capacity as head of a department in the Foreign Office.

Ernst Fetterlein and his wife shared at least two Christmas dinners with the Dennistons. Conversation was difficult, as Mrs Fetterlein did not speak English and her husband’s only common interest with AGD was work. Robin Denniston remembers Mrs Fetterlein being large and Mr Fetterlein small, formally dressed with boots and a monocle. They always came bearing gifts for the Denniston children.

Ever the frugal Scotsman, AGD kept immaculate records of his finances throughout the year and compiled a month ledger. October showed £155-9-5 received and £155-10-5 paid. November showed his account balanced at £80-7-9.

***

By the beginning of 1941, GC&CS had developed functions other than cryptanalysis and some of these seemed more appropriate for the Signals or Intelligence Departments of the Ministries. At the same time, the War Office and Air Ministry virtually controlled the activities of their respective Service Sections at GC&CS, while the CSS had control of policy over the output of Enigma cryptanalysis. Menzies presided over the Y Board and in effect sat between GC&CS and the Services. In November 1940, Colonel Butler of MI8 approached AGD about moving the seventy members of CIS to BP. The driver for this was to place W/T intelligence (WTI) and cryptography work in one location.40 AGD’s reluctance to take them all was based simply on a lack of space but this was seen as a lack of vision on his part as well as administration inefficiency. It was thought that AGD wanted to preserve GC&CS as a purely cryptanalytical bureau and stop it evolving into a Sigint Centre. The prevailing view of some such as Group-Captain Blandy was: ‘I think it is perhaps as well to emphasize that Cryptographers are not intelligence officers, but only exist for providing the material from which Intelligence is produced, and it is as well to keep the intelligence side as far divorced from the cryptanalytical side as possible.’41

The Admiralty was quite content with the arrangements at GC&CS, and Captain Sandwith wrote that naval ‘cryptography and W.T.I. are both carried out at B.P.’.42 As far as the War Office was concerned, there should be greater Services control of GC&CS and the Y stations. GC&CS’s output had ‘greatly exceeded our expectations and pre-war forecasts’, and Travis went on to say: ‘From 1919-39, the interception services were very definitely run by G.C. & C.S., and it is only since the appointment of senior officers to A.I.1 E and MI8 on outbreak of war that any change has been desired, it is now urged that cryptography is subservient to interception. It is quite obvious that cryptographers will always know more of interception than the interceptors can possibly know about cryptography’.43 The issue came down to whether or not Y included cryptanalysis. DMI and D’s of I said it did, DNI and CSS said not. In January 1941, the latter view prevailed at a meeting of the Y Board: ‘The Board discussed at length the definition of “Y” Services and it was ultimately agreed that “Y” indicated interception and the development of all means of interception which might produce intelligence but did not include cryptography and its fruits.’44

There still remained the task of defining the relationship between Y and cryptography. On 2 July 1941, a sub-committee of the Y Committee reviewed the issue and concluded that:

There do not exist two mutually exclusive subjects that can be defined by these names. The two are so inter-related if not very consistent or even, perhaps, legally sound, a compromise which may be expressed (necessarily loosely) thus:

The ‘B.P. Committee’ was set up and had its first meeting on 25 February 1941, with AGD’s objective being ‘to bring forward matters concerned with cryptography and anything that might arise there from’.45 It quickly turned into a GC&CS all-purpose committee and petered out after a few meetings.

At the suggestion of Group Captain Blandy, the Y Committee appointed a special ‘E’ Committee on 12 March, consisting of military and air force members and Y station commanders with Travis as chair. They met at BP so Travis could pull in staff as required.46 It confined its work to the requirements for Army and Air Force Enigma traffic and, at its final meeting on 18 November 1941, decided upon an ‘E’ interception plan for the future, with interception carried out on an Inter-Service basis around four stations – Beaumanor (Army), Chicksands (Air Force) with Whitchurch and Harpenden in support.47 This was approved by the Y Committee several weeks later.

Y Interception was controlled by a structure overseen by the Chiefs of Staff. AGD sat on the Y Board chaired by CSS and Travis sat on the Y Committee reporting to it, chaired by Air Marshall Sir Philip Joubert. It in turn had Sub-Committees: Technical, Administrative, ‘E’ and a Noise Investigation Bureau for non-Morse traffic. MI8 still wanted some kind of ‘Operational Intelligence Section’, but unlike the Admiralty that had OIC, it, unlike MI8, was a Command. All military units engaged on aspects of army-air WTI work were combined into a single group on 25 March 1941 called Intelligence School No. VI or 6 I.S. The exception to this was a group called the Special Liaison Party (SLP) which worked in Hut 3 at GC&CS. 6 I.S. eventually moved to Beaumanor in July along with the War Office Y Group (WOYG) in October. This was compatible with the Board’s official ruling that Y did not include cryptography and that the two were indivisible was acknowledged by the appointment of a cryptanalyst from 4 I.S. to command 6 I.S. An MI8 officer was sent to GC&CS to represent MI8(a), the intelligence branch of MI8, and to act as ‘the channel through which intelligence from traffic analysis reached the War Office’. He produced a weekly report of the ‘changes in the German W/T picture as shown through decodes, and aiming at adding to the fund of intelligence produced by G.C. & C.S’.48

AGD had recommended the creation of an ‘Interservice Distribution and Reference [D & R] Office’ at BP to counter Service dissatisfaction with the apparent lack of uniformity and standardisation in the reporting of Service Sigint products. While diplomatic sections had a uniform and tidy routine through a D & R, naval, military and air Sigint was subdivided among a large number of units, Service, inter-service and partially inter-service with separate outlets to different customers. A Service D & R with a civil head and Service intelligence officers attached to it would ‘assure the Directors that their Intelligence Divisions were fully represented at the centre and their interests in the circulation of the results completely covered’.49

The proposal was approved by DMI50 and DNI51 and then by the Y Board on 14 February. However, opposing factions within the Ministries and GC&CS caused the proposal to collapse. Part of the problem was that Army and Air Force decrypts were disguised as agents’ reports, with all indication of wireless origin removed. According to de Grey ‘It would have been difficult to contrive a system more likely to prevent signal intelligence from ever being of the fullest use to its recipients.’52 The system had worked for Diplomatic Sections because they had little interest in the problems of interception or W/T in general.

In April 1941, de Grey suggested a D & R with two main functions:

To receive the cryptographic output of the various sections of G.C. & C.S. and ensure that such intelligence as they produced was passed to other sections who might be interested, with a view to aiding cryptography;

To ensure that all information likely to interest the three Service Ministries was passed to the Intelligence Officer of the Service Sections of G.C. & C.S., so that such information may reach the Ministries in as intelligible a form as possible.53

AGD reported to the JCC on 14 July that he had set up a new section called the Intelligence Exchange (IE). It was to be headed by de Grey and include an officer from each service. Its remit was to receive and analyse the complete daily output from each Section at BP and include Diplomatic, Naval, Military, Air, Hut 3 (Joint), Russian, French Naval, ISOS (Intelligence Services, Oliver Strachey) and Commercial. They would then be in a position to see that all the Ministries received what might interest them. The exception to this would be Hut 3 as it already served the three Service Ministries and there was no question of reissuing any of its product. This was not the ‘D & R’ that the Service Ministries were expecting and,

only the Admiralty complied, sending an officer from N.I.D., who had no familiarity with and no adherence to Naval Section or to I.E. He proceeded to institute direct reporting from I.E. to N.I.D., so upsetting the principle for which I.E. was then fighting, namely, the unification of the channels of reporting, and the principle for which Naval Section was contending, that Naval Section should be the only channel to the Admiralty. His attachment was of short duration.54

The appointment could be seen as an attempt by DNI to safeguard his interests at GC&CS, as unlike the Army and Air Force Section’s subordination to their respective Ministries, Naval Section was not subordinated to NID. In any event, DNI had already appointed Captain J.R.S. Haines, RN, as his liaison officer with the title Assistant Director of the Operational Intelligence Centre (ADIC), with the following remit:

He will visit B.P. frequently to facilitate cooperation between N.I.D. and B.P. and will be responsible to D.N.I. for the coordination of the results of the work of the Naval Section at B.P. and for the action taken by N.I.D. on the material provided by B.P.55

This arrangement, according to Birch, ‘enduring for the rest of the war and proved an unqualified success’. I.E. became a ‘comprehensive up to date library of G.C. & C.S. output’ with Naval Section remaining ‘its most constant supporter’.56 With a flood of GAF Sigint pouring in from the Y stations, the Air Ministry’s Directorate of Intelligence was upgraded in the spring of 1941.

***

Intelligence obtained from non-military sources was predominant in GC&CS before the war and in wartime continued to be overseen directly by AGD. This part of his organisation operated purely as a cryptanalytical bureau, limited to the decryption and reporting of enemy and neutral diplomatic and commercial communications. The Section had moved to BP from Broadway Buildings (part of Commercial Section) on 26 August 1939, with around ninety staff comprising some thirty on a Senior or Junior Assistant grade (cryptanalysts with varying degrees of experience, in some cases gained in WW1) and some thirty support staff (Higher Clerical Officers, Clerical Officers and Clerical Assistants); the remainder were typists, traffic-handling staff and office keepers. The structure remained as it had been before the war, with AGD as Head with a Registry; the Distribution and Reference Section with its own typists; the Traffic Section; a large number of country sections, each separately responsible to AGD, and some cryptanalysts engaged in specific research problems outside the framework of sections. This last group, consisting of three experienced men and several juniors, was engaged in advance problems such as Enigma (in support of the Services Sections) and the Japanese ‘Purple Machine’. The move went smoothly, with no interruption to its output. AGD was based in the Mansion, while the Section occupied Elmers School which provided working accommodation for some sixty people. The Senior Assistant of Distribution and Reference had day to day administration responsibility for sections at Elmers School, while AGD remained in charge of policy and progress of sections whose heads continued to report directly to him.

The Distribution and Reference Section maintained contact with the users but according to Birch ‘the producers were not concerned with traffic analysis intelligence or the use of their products and were in general ignorant of even the sources of supply of their raw material’. The key ‘country’ sections were Italian, Japanese, Near Eastern, Chinese, Balkans, Portuguese and French, which was disbanded in May and reconstituted after the fall of France to deal with Vichy government traffic. The traffic of twenty-six countries had been studied, 70,000 out of 100,000 telegrams received, with 8,495 translated and circulated. At the same time, 135,000 coded or plain text messages had been circulated by the Commercial Section (with thirty-nine staff). There had not been a German section since 1919, because following the publication of the Zimmermann Telegram, German diplomatic ciphers used two very high-grade systems, one of which was an OTP. No breaks had been made and only one cryptanalyst was assigned on a ‘care and maintenance’ basis.

Seven-day-a-week working was introduced shortly after arrival at BP and a two-shift system was later introduced due to a shortage of space. Adjustments had to be made to the work of the section to take account of wartime priorities. The diplomatic and consular communications of Axis countries could reveal military plans as well as their military and industrial resources. Those of neutral countries who had representatives in enemy countries might reveal similar information as well as their own intentions. It was felt that Allied countries and safe friends did not need to be covered. Work on German diplomatic traffic was treated like a research problem, with German Service problems being a priority. However, a veteran of Room 40 took up the work and when one of the systems in use was identified (the OTP) in 1941, collaborative work with the Americans could begin. The Italian, Near Eastern, Balkan and Chinese Sections were reinforced as was the Japanese Section when linguists were found. The French Section had been disbanded in April 1940.

The Diplomatic Section benefited from the recruitment of the fiftysix seniors and thirty women linguists upon the outbreak of war. While the majority went to the Service Sections, some were sent to Elmers School and were immediately useful. Working space was barely adequate to house the peacetime staff, but this was solved temporarily by moving the Commercial Section back to London. This freed up an outbuilding but it was demolished by a stray bomb on 20 November 1940.

Italy’s entry into the war allowed the Diplomatic Section to demonstrate that more than political intelligence could be obtained from the enemy’s diplomatic and consular communications. It could reveal their military strength, intentions and plans for espionage and economic war. GC&CS had access to traffic from the Italian embassies in Moscow, Madrid, Lisbon, Washington and Tokyo. Legations in the Balkan capitals had military attachés who talked openly to Rome of German military movements until the Germans subsequently stopped their telegrams. Their representatives in the Near East, South America and Ireland along with their consuls at Lourenço Marques (now Maputo, the capital of Mozambique) and other strategic points, frequently reported on Allied convoys. Much of this traffic was now readable and by July 1942, twenty-five communications per day were being translated and issued. The Italian Section was placed on a 15-hour watch when Italy entered the war and on occasion this was extended to a 24-hour watch. The Section was reinforced to nineteen staff so that even low-grade traffic could be covered. Further traffic was obtained when the Admiralty cut the undersea cable running from Malaga to Genoa, forcing the Italian Embassy in Madrid to use W/T. This provided access to invaluable intelligence about the Spanish Government’s relations with the Axis countries.

In September 1940, the Commercial Section moved to Wavendon House in the village of Wavendon near BP to avoid London bombing. By the end of December 1940, it had thirty-nine staff. In 1940 it circulated 135,000 messages either in code or as plain text to the Ministry of Economic Warfare (MEW) and to the Information and Records Branch of censorship. Many of these were also circulated to the Admiralty, War Office, Air Ministry and the Ministry of Shipping.

The success of GC&CS’s diplomatic and commercial sections, under AGD’s direct control, would prove to pave the way for events which played out later in the war. The academic David Alvarez has provided a comparison between the records of GC&CS and the US’s SIS in reading foreign diplomatic codes.57 It provides reasons why the US would stand to benefit significantly from any collaboration with Britain:

British codebreakers for example had solved high-grade Italian ciphers while the Americans were struggling to master low-grade versions. GC&CS was reading several Vichy French diplomatic ciphers at a time when the SIS was hoping that the next staff increase might free up one or two officers to open a French section. GC&CS routinely solved Balkan and Near Eastern systems that did not even appear on the cryptologic horizon of the SIS. Even in the matter of Japanese codes and ciphers (an American speciality) the British were reading more systems (including Red) than the Americans, although GC&CS had had no more luck with Purple than their cousins across the Atlantic. Only in the area of German and Russian communications were the prospective partners equal. In their efforts against Berlin’s diplomatic systems neither had been able to advance beyond the reconstruction of the DESAB code. As for Russian systems, neither was studying Moscow’s diplomatic ciphers, although GC&CS was reading a few Red Army and Comintern systems.

Throughout 1941 BP’s Service Sections continued to expand. There were six separate naval sections four of which covered German, Italian, Spanish and French traffic. Hut 8 dealt with German Naval Enigma and Knox’s section handled Italian Naval Enigma. Japanese naval Sigint had been passed to FECB and the staff had moved to the Japanese Diplomatic Section. Most of the French traffic was being read, but very little of the Italian traffic apart from Italian Naval Enigma, solved by Knox. For German naval work, there was an organisational division between Hut 8, which was tackling the Enigma problem and the German Naval Section, which was dealing with everything else. However, Hut 8 supplied the decrypts and German Naval Section, which became known as Hut 4, provided W/T cover, traffic analysis and relevant intelligence. At this time only two Bombe machines were operational although eighteen had been ordered. According to Birch: ‘The sum total of cryptanalytic success on German naval systems of all grades and kinds cannot be said to have as yet achieved much operational significance.’ Furthermore:

The most significant achievement of German Naval Section in 1940 was the control it had over its own domain. At the beginning of the war, it did no cryptanalysis, because it had no cryptanalysts; no traffic analysis, because ‘operational intelligence’ was the monopoly of 8G; no general intelligence because there was none from Sigint sources. By the end of 1940 it had established a monopoly of all naval Sigint undertaken on German sources at G.C. & C.S. – even the raw products of Hut 8, the only exception, passed directly to it for processing and issue – and was already the champion of the ‘one Service, one Section’ principle as opposed to the interservice and the functional theories, for the proper organisation of G.C. & C.S.

While there was a considerable amount of operational intelligence coming from traffic analysis, the Admiralty was not convinced of its reliability. Birch, in his capacity as Head of the Naval Section at BP, had written to AGD on 20 October 1940:

Apart from questions of efficiency and convenience here, there cannot, from the point of view of Admiralty, be several separate entities at B.P. independently responsible for supplying them with intelligence and its interpretation. The German Naval Section is the responsible body and Admiralty rightly holds it so. To them it’s no excuse at all for me to say: ‘Oh, yes, we’re the German Naval Section, but this bit of intelligence is done elsewhere, so I’m not responsible.’ It merely looks like a phoney alibi; it brings the Section into disrepute and makes B.P. look like a badly organised muddle.

The Military Section differed considerably from the Naval Section. It was part of 4 I.S. and controlled by MI8 with its head, Tiltman, responsible to DMI in the War Office as well as AGD. At this stage it had no Enigma traffic to work on as it had handed over Japanese work to FECB and Italian work to CBME. It devoted most of its staff time to the cryptanalytical problems of other Services. Tiltman was the leading cryptanalyst at GC&CS, although his role was not formalised until the following year and Military Section tended to become synonymous with his functions. Examples of this were the Russian Section created in March 1940, the setting up of an inter-service school for the training of cryptanalysts called Interservice Special Intelligence School (ISSIS) and a Research Section to tackle tough cryptanalytical problems.58

Air Section, like the Military Section was separated from Enigma traffic and under the control of a Ministry Section, AI1(e). However, it had had great success and could claim to read all GAF non-machine ciphers, including four German, five Russian and two Italian meteorological ciphers. It did not report or interpret the decrypts, as this was done in conformity with the Ministry’s policy of decentralisation at Cheadle from where it was sent on to AI(e). Air Section was subordinate to AI1(e) whose view was that their function was purely cryptanalysis. Any effort to fill the many gaps in RAF intelligence from Sigint sources was discouraged and direct contact between them and AI3(b), Fighter Command and Bomber Command was denied as long as possible. A Fighter Intelligence Subsection had been formed in Air Section to study W/T traffic in December 1940, and the following month, a member of Hut 3 and a computer59 from Cheadle formed a subsection called SALU to tie up information between low and high grade sources. The work of both sections was ignored by the Air Ministry. Air Section also housed a meteorological service which provided weather data for British forecasting services in preparing weather forecasts for the RAF and, later in the war, the US Air Force.60

Another valuable source of intelligence for AGD’s organisation was from the German military intelligence organisation, the Abwehr, headed by Admiral Wilhelm Canaris. They used a version of the Enigma machine to encrypt their communications with agents abroad. The system was broken at BP in 1940 by Oliver Strachey and his ISOS team. The intelligence was sent to SIS’s counterespionage branch, Section V, which was located in St. Albans, about 26 miles from BP and the same distance from Whitehall in London. The intelligence war station in St Albans was headed by Captain Felix Henry Cowgill, who spoke about their work after the war:

At first they were little more than fragments of German intelligence signals, in German, and either meaningless or almost so. But in a surprisingly short time, certainly less than a year, we were reading Canaris’s traffic and that of the Sicherheitsdienst [the intelligence agency of the SS and the Nazi Party] too. From that basis we could, therefore, work towards first the control of the German intelligence service wherever and whenever it appeared, and then the liquidation of that service.61

Secret service communications were intercepted by the Radio Security Service (RSS) and worked on by the ISOS at GC&CS, although the cryptanalysts were working for SIS. By the end of the year, RSS had become the unit responsible for the breaking-down of the global communications of the enemy secret services. They relied on Post Office Y stations and amateur wireless operators throughout the country. They grew from 150 at the beginning of the war to 1,000 strong.

The internal organisation of GC&CS juxtaposed individual Service sections. This facilitated the sharing of experience, interchange of personnel, collaboration on common problems, pooling of research and machinery. The exception was the complete fusion of German Army and Air Force Enigma in Hut 6. They handed decrypted messages to Hut 3, who camouflaged the decrypts as agents’ reports and by-passed the official Sigint sections MI8 and AI1(e), going directly to the Country Sections, MI14 and AI3. MI8 and AI1(e) did place staff in Hut 3 with a section called 3M advising on Military Intelligence and another section called 3A advising on Air Intelligence. Both of these sections disseminated material to ministries and commands.

Travis took charge of mechanical aids to cryptanalysis, and as the Bombes were used by the cryptanalysts of all Services, his command included Huts 6 and 8. Therefore, Hut 8 was divorced from Naval Section and Huts 3 and 6 became separate entities. Other variants of Service ciphers were attacked by a small and separate group led by Knox.

Knox persisted with his complaints throughout 1941 and AGD made one final attempt to explain the situation to him on 11 November 1941:

My dear Dilly,

Thank you for your letter. I am glad that you are frank and open with me. I know we disagree fundamentally as to how this show should be run but I am still convinced that my way is better than yours and likely to have wider and more effective results.

If you do design a super Rolls Royce that is no reason why you should yourself drive the thing up to the house of a possible buyer, more especially if you are not a very good driver. I lost any confidence you had in me when I disagreed with you in Dec. 1939 and said that you could not exploit your own success and run huts 6 and 3. I was right – you broke new ground while the building in your foundation was carried on by Travis etc. who, I say, were better adapted to this process than you.

our next big show was K. You alone among us found the way but the full value of your work could only be obtained by fitting results into the full picture in the Naval Section.

And now comes your latest effort which only proves again that you are the right man in the right place. You told me of a side-line in Intelligence that you wanted to develop. I agreed but begged you to remember your real metier. So you produced this result which none other of our party could have done.

You say you did it because you are a scholar who proceeds from his raw material to his finished text, well – who is preventing you – you have access to all past material and copies of all new.

What are my grocer’s window dressing. Eric Smith offers all productions in neat form to those who need them. Birch ties up information from every naval source and tells the story. Hut 3 collects and reports accurate information derived from the source you invented.

Do you want to be the inventor and the car driver? Do you want to be Eric Smith, Strachey, Birch and Wing-Commander Humphreys and De Grey wrapt into one which will include Knox who is the source? If so I don’t agree and I don’t mind at all what steps you take.

You are Knox, a scholar with a European reputation who knows more about the inside of an Enigma machine than anyone else. The exigencies of war need that latter gift of yours though few people are aware of it.

The exploitation of your results can be left to others as long as there are new fields for you to explore.

I do disagree with you.

Yours ever,

A.G.D.62

Alas, it was to no avail and, demonstrating an astonishing amount of arrogance, Knox wrote directly to Menzies. It is remarkable that AGD continued to treat Knox in a professional manner given the apparent contempt which Knox seemed to hold him:

Though it was not my business, since I was ordered to do something else, I devised a theory which reduced, often to a twentieth part, the time necessary to be expended on the solution of a day’s messages, a method which, for at least nine months had escaped the Polish bureau. Having earned thereby still greater unpopularity with Commander Denniston, I was powerless to insist that the whole affair was still in an experimental stage, that watches should be constituted, that the best brains should be employed, and that we should be prepared when ‘the war should begin’. The hut had, since Commander Denniston laid it down, to remain in charge of one officer physically unfit for night work, a very able worker of no marked push or originality. In consequence when the push came watches often possessed workers of the highest ability but unused to certain minutiae, and some early and vital keys were lost. For this Commander Denniston’s mandate was responsible.

When a cipher is out Commander Denniston is willing to parade superiors round sections of whose work he understands literally nothing and to assume credit for achievements his mismanagement nearly ruined.

Two things remain to be said. As to my right to criticise I need only remind you that I am a Senior Cryptographer. At the end of the Great War Commander Denniston (with a staff of about 30) was administering one of the German Fleet Cyphers and I (with a staff of three) another. If memory serves me at the end of the war the smaller unit was supplying copious and accurate information, while the larger remained silent. Secondly, Sir, if you criticise me on the score that I have accepted money in peace time and desert during hostilities I need only say that neither Commander Denniston’s friends, if any, expected, nor his many enemies feared that, on the outbreak of war such responsibilities should be left in hands so incapable.63

***

On 8 February 1941 a meeting took place in AGD’s office at BP which many historians believe heralded the start of the ‘Special Relationship’ between Britain and the US. However, intelligence cooperation between the two countries can be traced back to WW1.64 In July 1917, General John Pershing, commander of the American Expeditionary Force (AEF), decided that his intelligence staff (G-2) should follow the model of their British counterparts in the BEF. Pershing kept his distance from the British Army and its commander, Field Marshal Sir Douglas Haig, but did establish a good rapport with the French commander, General Philippe Petain. Major Dennis Nolan (later Brigadier General) was head of Pershing’s intelligence staff. He established a good working relationship with the head of the BEF’s intelligence staff, Brigadier General John Charteris. Charteris revealed details of the British intelligence system, including Sigint, and, after a presentation to the AEF by Charteris, Pershing approved the subsequent intelligence regulations on the British model without amendment. The British agreed to provide both document-based and training support.

The AEF’s decision to copy from the British brought junior intelligence officers from both armies into close contact. In 1917 Major Stewart Menzies was responsible for counter-espionage at BEF GHQ, where he established close links with his opposite numbers. By 1941, he had become Major General Sir Stewart Menzies, head of the British SIS. In 1918, William Friedman was a cryptographer working for the AEF G-2. By 1941, he was head of the American Signals Intelligence Service and had established close links to AGD. As for AGD himself, while not directly involved in Room 40’s work on the Zimmermann Telegram, he had witnessed first-hand how Admiral Hall and the American, Edward Bell, had worked closely together. The outcome of their collaboration had, in effect, brought the US into WW1. So AGD understood full well the potential benefits both to Britain and his own organisation, of a close working relationship with US intelligence services.

The 1941 meeting in AGD’s office had its origins in an informal visit to London in July 1940 by William Donovan, a special envoy of President Roosevelt. His visit had been prompted by SIS’s new representative in the US, William Stephenson, and his task was twofold: to assess Britain’s determination and ability to continue with the war, and see whether closer collaboration could be arranged with the Admiralty on intelligence. At the end of August, the British Government invited the American Military Observer Mission to attend a meeting in London with the British Chiefs of Staff. While the purpose of the meeting was to discuss the ‘Standardisation of Arms’,65 Brigadier General George Strong told the meeting about ‘the progress his Service was making against the Japanese and Italian ciphers and formally proposed to the Chiefs of Staff that the time had arrived for a free exchange of intelligence’.66 Interestingly, the US naval representative at the meeting, Admiral Ghormley, said nothing about cryptanalysis and the British offered nothing in return. Donovan returned to Washington and recommended a full and direct exchange of intelligence between the two countries’ naval intelligence departments.

Within several months, the US Navy’s position had changed dramatically and Ghormley attended a meeting in London on 22 October with DNI John Godfrey and Menzies. The following day in Washington, Secretary of War, Henry Stimson, met with Secretary of the Navy, Frank Knox, to discuss sharing of information with the British on ‘the code methods of the Germans’.67 By the end of December, an Anglo-American pact on cryptanalysis had been agreed with the intention of sharing with each other, information about the codes and ciphers of Germany, Italy and Japan.

On 7 February 1941, four passengers disembarked from HMS King George V after she had anchored in Scapa Flow, the Home Fleet’s remote base in the Orkneys. Abraham Sinkov and Leo Rosen worked for the US Army Signal Intelligence Service, and Robert W. Weeks and Prescott H. Currier were US Navy communications officers. Sinkov was a late replacement for William Friedman who was unable to travel due to illness. They were greeted on the quay by a naval officer68 and several drivers for the two staff cars and a lorry which were at their disposal. The equipment that they brought with them would not fit on the aircraft sent to meet them, so they were transferred to another dock where they boarded a Royal Navy destroyer. It took them south, along the coast of Scotland and England to the Thames and London, docking at Tilbury. They travelled through London and late on the evening of 8 February arrived at BP, becoming the first Americans to do so. Remarkably, they brought with them perhaps the greatest achievement of US cryptanalysis during WW2. Japan had developed a high-level cipher machine to encrypt its diplomatic traffic and, like the Enigma system, it was also used to decrypt messages. The American SIS team under William Friedman and Frank Rowlett had broken the system, angoo-ki taipu b (Type B Machine – codenamed ‘Purple’ by the SIS) and subsequently were able to build replica machines. Their gift to the British was one of their replica machines,69 along with other codebreaking material

Before their departure, the Americans had been briefed on the importance of security in all aspects of their engagement with the British:

All members of the Delegation were asked to pledge themselves to secrecy to the extent that the secret should only be told in the case of the Navy Department to the Director of their Cryptographic Bureau and the case of the War Department to their DMI, Director of Sigs., and their Chief Cryptographer, and moreover we disclosed them only our cryptographic methods of solution and asked them not to request to be shown the resulting intelligence.70

After arriving at BP, the American party was taken to AGD’s office, where they were greeted by him along with Travis and Tiltman. AGD’s personal assistant, Barbara Abernethy had been tasked with providing sherry for the guests and she managed to carry a large wooden cask from the Army and Navy Stores to the Mansion House at a spot adjacent to AGD’s office,71 from which she duly served sherry to all assembled there. They were then driven to their billet. According to Currier: ‘Now our billet was the country home of the chairman of the board of the, at the time, Anglo-Persian Oil Company, an extremely wealthy man. He had turned over his entire house to these four travelling Americans, fully staffed, the larder full, with a butler and three upstairs maids and a cook to take care of us for the time that we were there.’

The Navy and Army groups were split up and never travelled together while visiting BP’s outstations or parts of BP itself. Currier and Weeks spent much of their time in the Naval Section and visited naval intercept stations such as Scarborough. All four were given details of the Enigma machine and shown the Bombe machines in operation.72 On 3 March, AGD informed Menzies that, ‘Our American colleagues have been informed of the progress made on the Enigma machine.’ Weeks wrote to AGD to assure him that all information about the Bombe machines would be treated with the utmost secrecy:

For: Commander Denniston

3/3/41

We are in accord with the purport of your memorandum of today.

We undertake to vary out all instructions for the preservation of the secrecy of the work mentioned, informing by word of mouth only the head of our section, Commander L.F. Safford, USN.

In connection with the naval aspects of the above work we deem it advisable to obtain the wiring of interest to us (i.e. the device on which Turing is working), and to disclose that only when it is decided to work on the problem. In such an event we shall observe all precautions and keep you informed of our actions.

As far as is practicable we shall make arrangements for the forwarding of communications through our naval attaché, as mentioned by you.

Respectfully,

R.H. Weeks’

The Americans boarded HMS Revenge at Helensborough in the Clyde several weeks later for the journey home. On 19 March, Weeks wrote to AGD with a list of the materials that they had received from GC&CS.73

AGD had overseen the visit by the Americans despite serious health problems. On 27 February, he was X-rayed by a consultant called Shanks at 68 Harley Street and a gall stone was found in his bladder. Yet two days later, he invited the Americans to lunch where his family were billeted at Stapleford Mill Farm. On 10 March, he went for a further consultation in Harley Street and subsequently underwent surgery at Luton General Hospital on 13 March. He was not discharged until 14 April but shortly afterwards he had an attack of orchitis and he was again hospitalised on 20 April, this time at Ashridge Military Hospital at Ashridge Park, Berkhampstead, Hertfordshire. He did not return to BP until 27 May by which time his hospital bills had taken up a third of his monthly salary of £98.

One of the outcomes of the visit of the Americans to BP was that AGD agreed to visit the US and Canada to discuss further collaboration between the three countries. He cabled Washington on 28 July, informing them of his plans, which were to travel from Scotland on 11 August using American transport. He hoped to arrive in Washington on the 12th or 13th and following meetings there and in New York, he planned to visit Ottawa.74 AGD duly departed for the US as planned and after stopping briefly in Newfoundland on the 12th, he eventually arrived in Washington. On 14 August 1941, Travis telephoned the Denniston house (telephone number – Soulbury 7) to see if Mrs Denniston was okay. He subsequently cabled AGD that same night with a message that all was okay at Soulbury 7.

AGD met with William Friedman and members of his SIS team75 in Room 3341 of the Munitions Building on 16 August at 9.00 am. The purpose of the meeting was to prepare a schedule for his visits to the various sections of SIS from 19 to 22 August. Apart from Friedman’s own team, which consisted of Sinkov, Rosen, Rowlett and Kullback, also present were SIS Executives Lieutenant Colonel R.W. Winckler, Captain H.G. Hayes and Captain E.F. Cook. The schedule that was agreed included visits to SIS’s German, Italian, Central and South American, Japanese Diplomatic and Army Sections. The final day would be spent visiting SIS’s tabulating and machinery, intercept and school sections. AGD must have been reassured that SIS was keen to cooperate fully with him. During a three-hour meeting, he reciprocated by giving a brief report on the probable status of cryptanalytic work engaged in by certain other governments, in so far as the facts were known to him. He also reported that cooperation between GC&CS and the recently established Canadian cryptanalytic section in Ottawa, the Examination Unit, was wholly dependent on the removal of Herbert Yardley from that organisation. Yardley had written a sensational exposé of American and British cryptography in WW1, The American Black Chamber, in 1931. Despite Yardley’s endorsement by General Mauborgne, the US Army’s chief signals officer, his views were not shared by others officials in US intelligence services.76 They also agreed on a more safe and direct forwarding and exchange of documents.

AGD hoped to convince Friedman that there were no spare Bombes to give to the Americans and that he should not waste valuable resources by commissioning one from IBM. He also wanted to persuade SIS that it should leave efforts against European military work to the British. When the American Army began to be involved directly in the European theatre, the British would reveal more about its methods and supply information where appropriate. AGD also offered to have some of SIS’s mathematicians visit BP, despite his security concerns. One of AGD’s key objectives was to persuade Friedman’s team to concentrate on Japanese systems, given that he assumed they had vast technological resources to deploy against them. When he toured SIS facilities, however, he was disappointed to see how little space and equipment they actually had. But Friedman was receptive to AGD’s advice, and accepted that a British Bombe was not available. Furthermore, the meetings between AGD and Friedman established what would become a lifelong friendship. In a letter to AGD’s son Robin years later, Friedman’s close colleague in SIS, Frank Rowlett, said of the visit: ‘I remember well your father’s visit to Washington in 1941. It was his visit which laid the foundations for the collaboration between the cryptographic activities of the US and the UK which produced intelligence vital to the successful prosecution of WW2. We spent considerable time together discussing the technical activities undertaken by both countries and worked out some of the details of our early collaborative efforts.’77

AGD’s diary shows that he dined with senior staff of the US Navy’s OP-20-G group at 20.30 on 18 August and SIS on the 19th. While his dinner with OP-20-G was cordial, his reception when he arrived at their offices was anything but. He was shown around the OP-20-G offices by Currier before meeting with the leaders of the naval communications section. AGD was agreeable to providing more information about French and Italian systems and improving the security of naval communications with their British counterparts.78 Several days later he had a more difficult meeting with OP-20-G’s head Laurance Safford who had a history of Anglophobia. In 1937, the State Department had requested approval for a British engineer to spend four months with Bell Telephone Laboratories and the Radio Corporation of New York. Safford’s reply on behalf of OP-20-G was: ‘The Director of Communications can raise no specific objections to Mr. Gee’s extended visit to the Bell Laboratories. However, it is considered an undesirable practice for this country to disclose its technical secrets to foreigners while getting nothing in return.’79 Despite the fact that the American Navy was virtually on a war footing in the Atlantic, AGD urged Safford to restrict his team’s efforts to nothing more than research when it came to European naval systems.80

When AGD met one of OP-20-G’s top codebreakers, Agnes Driscoll,81 it was clear that she was privy to some of the information that Currier and Weeks had brought back from their visit to Britain. It had been agreed that only Safford would have sight of British cryptographic secrets. One can only imagine AGD’s thoughts when he met Driscoll, aged 53 and a 20-year veteran of cryptanalysis. Her attitude and approach to cryptanalysis bore startling similarities to that of Dilly Knox! She rejected BP’s automated solutions based on mathematics and claimed to have developed a much better hand method based on intuition. Driscoll told him that she was evolving a method which would enable her to solve keys on a small amount of traffic. She went on to say that the American Navy did not want or need a Bombe machine and thought little of the British methods for attacking Enigma. She showed AGD a sample solution based on a short eight-letter crib and claimed that it would require only two dozen people a few days to find the Enigma settings using her soon-to-be completed ‘catalogue’. AGD maintained his composure despite the insulting nature of Driscoll’s comments. She could well have known of British successes against Naval Enigma in 1941. He offered to provide more information about the Bombe machines and Turing’s methods and even offered to supply OP-20-G with a machine when one became available. Furthermore he invited her to BP, but a serious automobile accident she had suffered in 1937 prevented her from travelling long distances.82 However, she did not offer to send a member of her team in her place, nor did she show any interest in a visit from a British expert.83 AGD explained to Driscoll that the British and the Poles before them had explored the catalogue approach which she was proposing to use. It had had limited success against earlier versions of the Enigma system but would be of little value against the more formidable German naval Enigma system.84 Finally, after further discussion, Driscoll conceded that she did not fully understand the Enigma system and she rather forcefully demanded that BP provide further information. AGD asked her to provide a list of questions which he would take back to his colleagues and he promised to provide answers to all of them. AGD, with only a limited knowledge of the Enigma system, must have been startled by how basic some of the questions were. She was clearly after just enough information to pursue her own methods.

AGD returned to England on 23August. The family had had no news of him and as the Battle of the Atlantic was in full swing, all they knew was that he had flown rather than gone by sea. BP was worried as was the family. By 8 pm on the 23rd they were waiting, worrying and wondering. To quote his son Robin:

There was a heart-stopping moment when we heard the crunch of car tyres on the farm track. Could it be? It was too much to hope. But it was. It had taken him 15 hours flying from New York to Gander, Newfoundland, across the North Atlantic to Prestwick in the bomb bay and thence to Hendon where he was collected and driven home. It was the best moment of all our lives. He had brought us presents, for me a green pullover with black and white borders. He had had an amazing week but he could not tell us anything about it. That did not matter, what mattered was that he was alive and okay.

AGD’s health was still causing him problems and his diary for 26 August records ‘neuritis returns’, but around 30 August he was on his way back to North America by air. He flew to Washington and then on to Ottawa the following day to brief the Canadians about British cryptographic achievements against Japanese codes. In November 1939, Canada had offered to help the Allied intelligence effort by setting up its own cryptanalysis unit, specifically to attack German, Italian and Spanish traffic.85. AGD had told the Canadians that to get into the business of breaking ciphers, they needed a ‘high-grade cryptographer of long experience’ who would need at least three months of training in Britain.86 They took his advice but, surprisingly, hired Yardley to set up and run their new cryptographic department, the Examination Unit. AGD arrived in Ottawa on 3 September to meet Canadian cryptographers and he was keen to press home the point that Britain wanted the US and Canada to concentrate on Japanese military ciphers while Britain looked after diplomatic material.87 Having ensured that he would not have to meet Yardley, AGD told Lester Pearson, assistant to Norman Robertson, acting Undersecretary of State for External Affairs, that Yardley had to go or there would be no cooperation between Canada and Britain. AGD offered to provide one of Britain’s best experts to replace Yardley, Oliver Strachey, a veteran of MI1(b) during WW1 and a member of GC&CS since its inception. Under pressure from Washington, Yardley’s contract was not renewed and Strachey arrived in early 1942, having refused to go to Ottawa until Yardley left the city. He brought with him his personal assistant, Miss Rogerson and keys to high-level Vichy and Japanese diplomatic codes, which initiated close cooperation with Washington and London. Although he did not speak or read Japanese, he helped break the Japanese code, which was very complex, since it used variations of kanji, hiragana and Romanization

AGD flew back from Ottawa via Gander. He arrived in Ayr, Scotland, at 11.30 am on 13 September, went on to Hendon and then home to Bletchley. As soon as he arrived back in Britain, AGD sought from his experts the answers to Driscoll’s questions. He also established detailed procedures to register and track all communications with OP-20-G and SIS. By October, GC&CS had provided answers to all of OP-20-G’s questions and also dispatched the specifications of Enigma settings, details of wheel wirings and all relevant intercepts for 1941.88 AGD also made enquiries about obtaining an Enigma machine for Driscoll and he then waited for her to honour her commitment to provide GC&CS with a description of her methods. While GC&CS cryptanalysts were extremely sceptical about these methods, AGD’s view was that ‘We are on a good wicket at present but can’t afford to neglect any side lines.’89 In the end, it was left to Turing to write a scathing critique in which he concluded that even if the majority of the settings of an Enigma machine were known, Driscoll’s method would take far too long to find a solution.90

In mid-December 1941, Driscoll finally sent partial details of her special method to AGD. By now, GC&CS had concluded that her method had failed and AGD was reluctant to provide her with further information. Perhaps to hide its own failures, the US Navy suddenly claimed that AGD had never sent the material requested by Driscoll. Safford’s superior, Leigh Noyes, sent a series of critical telegrams and seemed to support Driscoll and the power of her methods. AGD responded by saying that he had indeed provided the information and if the US had not received it, why had it taken so long to report this to GC&CS. Suddenly, in the days after the Japanese attack on Pearl Harbor, Noyes apologised and miraculously, the missing documents from AGD were discovered in the OP-20-G offices. However, friction between British and US intelligence agencies persisted and eventually reached the ear of higher authorities on both sides of the Atlantic. This would certainly play a part in events which would unfold at BP in the early days of 1942. Similarly, by February 1942, Safford had been replaced by Joseph Wenger and a new breed of US cryptanalysts began working in OP-20-G. It seemed that Anglo-American cooperation would at last be restored.91

***