It will be remembered that the formulation of a strategic or ‘overall’ deception plan was dependent upon decisions taken at the Teheran Conference. This conference met late in November and accordingly, on 6th December, the London Controlling Officer was instructed to prepare a deception plan for operations against Germany in 1944.1 This was accomplished during the ensuing three weeks and the plan was passed by the British Chiefs of Staff on Christmas Day of 1943.2
The object of BODYGUARD, as the London Controlling Officer’s plan was called, was ‘to induce the enemy to make faulty strategic dispositions in relation to operations by the United Nations against Germany’.3 It provided the basis for current deception in Europe as well as a framework for the cover plans which would be initiated in due course by the theatre commanders in support of their own operations. While the Supreme Commanders in the North-Western European and Mediterranean theatres were made solely responsible for their own operational cover plans, they were also given a share in carrying out the ‘overall’ strategic programme. The aim of this long-term deception was to persuade the enemy to dispose his forces in areas where they might cause the least interference with operations in France4 and on the Russian front. Italy was excluded because the campaign there was itself a containing operation. To SHAEF5 three specific tasks were given. They were to persuade the enemy to believe that Allied plans existed to take advantage of a withdrawal or serious weakening in any part of North Western Europe. This, it was felt, would help to keep their garrison troops at full strength. They were to induce a belief in a coming Allied attack on Northern Norway, to be carried out with Russian support in the spring, with the immediate object of opening up a supply route from Sweden; that we intended to enlist the active co-operation of Sweden for the establishment of air bases in Southern Sweden, whence we could cover an amphibious assault against Denmark from the United Kingdom in the summer. Lastly, since it would be ‘impossible wholly to conceal the gradual build-up of Allied forces and other preparations in the United Kingdom during the next few months’,6 they should try to indicate that Anglo-American strategy was dictated by caution and that there was no intention of invading the Continent until the late summer. The later invasion date was to be suggested in a number of ways. Shortage of landing craft was to be emphasised; the number of Anglo-American divisions in the United Kingdom available for an offensive was to be represented as less than was in fact the case; American divisions in the United Kingdom were to be reported as arriving incompletely trained; every effort was to be made to conceal the return of Allied divisions from the Mediterranean.7 All this would show that we were behindhand with our mounting programme. On the other hand, the scale of the assault, when at last it did come, was to be greatly exaggerated,8 thus magnifying the task which still lay ahead.
In addition, as has already been stated, the Supreme Commander was required to provide a cover plan in direct support of OVERLORD. ‘As soon as our preparations for OVERLORD … clearly indicate to the enemy our intention to undertake a cross-Channel operation the Theatre Commander must implement his tactical cover plan to deceive the enemy as to the strength, objective and timing of OVERLORD.’9
The SHAEF deception plan which embodied all these requirements, both strategic and tactical, received the name of FORTITUDE. Work on this plan was begun as soon as BODYGUARD had been approved by the British Chiefs of Staff.10 Let us consider the stages of its growth. The objects of FORTITUDE, which remained substantially unchanged from the appearance of the second draft on 11th January until the final plan was approved on 23rd February, were: ‘to induce the enemy to make faulty dispositions in North-West Europe before and after the NEPTUNE11 assault, thus—
(a) reducing the rate and weight of reinforcement of the target area,
(b) inducing him to expend his available effort on fortifications in areas other than the target area,
(c) lowering his vigilance in France during the build-up and mounting of the NEPTUNE forces in the United Kingdom,
(d) retaining forces in areas as far removed as possible from the target area before and after the NEPTUNE assault.’12
The plan proposed to give effect to these objects by encouraging a belief in three distinct operations.
First, there were to be the operations for the reoccupation of abandoned territories. ‘From 1st February, 1944, balanced forces are being held in readiness to occupy any part of North-West Europe in the event of German withdrawal or collapse.’13 Second, there was to be the Norwegian campaign. Third, the attack across the Dover Straits. The intermediate task of promoting belief in a postponed attack was not treated as a separate problem, but was woven into the story of the cross-Channel assault.
The ‘reoccupation’ operations required no further elaboration. On the other hand, SHAEF did not find the Norwegian assault as proposed by BODYGUARD wholly acceptable. ‘Sweden would be unlikely to concede her southern airfields to the Allies with Germany still in occupation of Southern Norway, and as an assault on Denmark demands the prior occupation of the Stavanger–Oslo area, the target for a deceptive operation should be extended to include this area.’14 This meant having two assaults, the original one on Narvik, to secure the supply route to Sweden, and another against Stavanger, as a stepping stone to Denmark. The next question to settle was the most suitable date for the attacks. It had been decided, in January, to postpone the real invasion from 1st May to 1st June. On the calculation that a German division would take about three weeks to move from Norway to France, it seemed that OVERLORD would receive the greatest benefit from the Norwegian threat if the Germans could be made to expect these attacks at the beginning of May. By that date the weather would be suitable and it would still allow reasonable time for the subsequent assault on Denmark in the late summer. Accordingly 1st May was chosen for both the Norwegian operations.
Finally, there was the Supreme Commander’s tactical cover plan to deceive the enemy as to the strength, objective and timing of OVERLORD. The fear that preparations for invasion would sooner or later give OVERLORD away unless we took preventive measures, though still as real as ever, had by now undergone some change. It will be remembered that in August 1943 the view had been officially expressed that after January 1944 it would be impossible to conceal from the enemy that such an operation was pending. January had arrived, however, and the worst fears had not been realised. Opinion now began to regard the month immediately preceding the invasion as the really dangerous time. ‘By NEPTUNE D minus thirty, the movement and administrative preparations and the concentration of air forces will be nearly complete and the concentration of craft and shipping will be between 70 per cent and 80 per cent complete for Operation NEPTUNE. Although the German Command would not necessarily expect immediate invasion by such a force against their present scale of resistance, the preparations and the type and location of the forces will begin to threaten the NEPTUNE area unless preparations for the concentration of similar forces are made in the East and South-East of England.’15
Although BODYGUARD had stipulated as objects of policy during the ‘intermediate’ period a late summer invasion and an exaggerated striking force, it gave the Supreme Commander a perfectly free hand with his tactical plan to deceive the enemy as he thought best, and although it still recommended him to choose a date for the imaginary assault later than the real D Day,16 it robbed this recommendation of its force by suggesting that when the time for tactical deception had arrived, a policy of ‘postponement’ would tend to lack plausibility. ‘When the enemy realises that cross-Channel operations are imminent, the story indicating that no cross-Channel attack will occur until late summer will tend to lose plausibility. At this juncture the tactical cover plan prepared by Supreme Commander, Allied Expeditionary Force, will come into force with a view to deceiving the enemy as to the timing, direction and weight of OVERLORD.’17 It is, of course, legitimate to point out that if such a policy were ever going to help us to influence German dispositions in our favour, it could only do so if it were sustained until the eve of the invasion. The Germans were hard-pressed on other fronts. The fact that they believed, in the spring, that we intended to attack in July rather than in June would have availed us little if they had ceased to hold that view when the cross-Channel operations were imminent. In any case, the policy of postponement was in effect the first instalment of the OVERLORD cover plan, since it related to the invasion armies, and as such was almost bound to colour any stories that came later. As will now be seen, the Supreme Commander’s plan upheld both the policy of postponement and that of an augmented striking force, with consequences which will presently be considered. ‘With a target date of 15th July, 1944, a cross-Channel operation will be carried out by a total force of fifty divisions, with craft and shipping for twelve divisions. The assault will be made in the Pas de Calais area by seven divisions, two east and five south of Cap Gris Nez. The follow-up and immediate build-up will be a further six divisions. The force will be built up to a total of fifty divisions at the rate of about three divisions per day.’18 Antwerp and Brussels were to be captured, and from this bridgehead an advance was to be made to the Ruhr.
It soon became evident that between the desire to divert attention from the invasion preparations and the desire to suggest the 15th July as the date for the attack against the Pas de Calais, there lay an irreconcilable conflict. No one could alter the timing of the real preparations for OVERLORD; they had to be ready by 1st June. If we were going to make sham preparations in the South-East in order to ‘shift the centre of gravity’ towards the Pas de Calais, these presumably would have to be advanced pari passu with the real preparations, but then what became of ‘postponement’? ‘In order, however,’ says the plan, ‘to minimise our state of preparedness as a whole, the preparations in the East and South-East should indicate a target date of 15th July 1944.’19 It was always rather difficult to see how this would work out. Assuming that the Germans, by the interpretation of their air photographs and by other means, were able to gauge with any degree of precision the imminence of the operations for which the observed preparations were being made, then, in the South and South-West, they would have seen preparations which indicated 1st June. In the East and South-East, on the other hand, the correct interpretation would be an attack on 15th July. Taking one’s stand at 1st May, 1944, the argument would appear to have been that if the enemy saw the invasion thirty days away in the South and seventy-five days away in the South-East, he might somehow or other strike a balance and give it a date between the two. Of course he might equally well have said that the invasion against Normandy was coming in thirty days and the invasion against the Pas de Calais in seventy-five days. This weakness was at once pointed out by Major-General N. C. D. Brownjohn,20 who put the argument even more strongly by suggesting that if the plan were executed as proposed, the delayed preparations for FORTITUDE SOUTH would not be discernible to the enemy at all before the real invasion. ‘It is believed that the discrepancy between concentration for Operation NEPTUNE and the preparations being made in East and South-East England is too great since, if a target of 15th July is taken in the East and South-East, no substantial physical preparations will be apparent to the enemy. It is believed more practicable to state that during this period the preparations in the East and South-East should proceed concurrently with those made for Operation NEPTUNE and should indicate a target date not later than that for the forces being deployed in the NEPTUNE area. This treatment is somewhat inconsistent with the story, but the change is believed necessary, as otherwise no threat will be apparent to the Pas de Calais area prior to D Day.’21 The point was also taken up later by Major-General C. S. Napier.22 ‘It has often been pointed out that the desire to indicate a state of unpreparedness up to D Day and the desire to conceal the target area by threatening the Pas de Calais before23 D Day conflict. If the idea of suggesting D plus forty-five as the real target date is not dropped about D minus twenty-one at latest, there is a risk of prejudicing … concealment of the target area because unreadiness in South-East England as compared with completed preparations elsewhere might be interpreted as indicating the absence of a threat to the Pas de Calais. I am aware how difficult the problem is and that the present proposals for activity in South-Eastern Command after D minus thirty are probably the best attempt at a solution, if we really must adhere to the attempt to give an impression of unpreparedness. But at every turn we come up against the practical difficulty of this attempt.’24
In spite of these opinions, D plus 45 remained the target date for the false operation.25 On the other hand there appears for the first time, in the Fourth draft issued at the end of January, a paragraph which brings us at least a step towards a resolution of the conflict. This paragraph was introduced at the instance of 21 Army Group. It says: ‘If before NEPTUNE D Day, however, it becomes evident that the enemy does not believe in the later target date, preparations in the East and South-East should be accelerated and the threat to the Pas de Calais be fully developed.’26 21 Army Group, who, as prospective executants of the operation, were at this time taking an active interest in the progress of the plan, held the view that it might be necessary to make the attack on the Pas de Calais seem both obvious and imminent if in the critical days preceding O VERLORD the secrecy of the real operation appeared to be breaking down. Writing to SHAEF on 25th January, 1944, Major-General F. de Guingand, General Montgomery’s Chief of Staff, said: ‘I consider that the enemy should be led to believe that from now on our target in Northern Europe is the Pas de Calais area. Once our efforts have failed to make the enemy believe that our attack will not take place before the late summer, we should concentrate on telling him that the Pas de Calais area is our early objective.’27
When the planning of FORTITUDE began, any attempt to deceive the Germans after the invasion had started was still regarded as a minor affair. The story was to be that ‘a force of one assault, one follow-up and four build-up divisions is assembled in and behind the Thames Estuary and the south-east coast ports to carry out a subsidiary operation in the Pas de Calais area with the object of drawing German forces away from the main target area.’28 On 25th January, however, General de Guingand raised the post-assault phase to a level of importance which it had not hitherto enjoyed. In criticism of the paragraph already quoted he said: ‘I do not agree with the object which has been given for the attack on the Pas de Calais. If we induce the enemy to believe the story, he will not react in the way we want. I feel we must, from D Day onwards, endeavour to persuade him that our main attack is going to develop later in the Pas de Calais area, and it is hoped that NEPTUNE will draw away reserves from that area.’29 This change being accepted, the final draft of FORTITUDE expanded the post-assault story from a modest diversion to a grand attack. Thus: ‘The operation in the NEPTUNE area is designed to draw German reserves away from the Pas de Calais and Belgium. Craft and shipping for at least two assault divisions are assembled in the Thames Estuary and south-east coast ports; four more assault divisions are held in readiness in the Portsmouth area and will be mounted in craft and shipping from NEPTUNE. When the German reserves have been committed to the NEPTUNE area, the main Allied attack will be made between the Somme and Ostend with these six divisions in the assault.’30 In accordance with the ‘pre-invasion’ story which remained unaltered, the Germans were supposed, before the invasion took place, to believe that there were two assault divisions east of the Straits of Dover and five along the south coast. After the invasion had begun, according to this new story, the landing craft on the south coast, having taken their five assault divisions to Normandy (and not to the Pas de Calais, as previously supposed), would return to England for the four additional ones destined for the Pas de Calais. The two imaginary assault forces east of the Straits, having already been established in pre-invasion days, would continue to exercise their threat during the later phase.
The postponed target date had already been criticised on the ground that it would make it difficult before the invasion effectively to shift the centre of gravity of our preparations from West to East. The decision to represent the Pas de Calais operation, after the real invasion had been hunched, as the main one placed another difficulty in the way of pursuing the ‘postponement’ theme. If, before the invasion, we sought to show ourselves weak and unprepared, what would be left to carry out the second and greater invasion when the first and lesser attack was seen to have engaged the bulk of our forces? From this point of view the proposal to increase the invading force to fifty divisions was an advantage. But this advantage was cancelled by encouraging a belief in the later target date through a simulated reduction of our strength before D Day. The only way of bringing the two stories into line would have been to suggest a very greatly accelerated rate of reinforcement from the United States between the beginning of June and the date chosen for the imaginary assault. But this would have placed a wholly unrealistic burden on shipping space. FORTITUDE sought a partial escape from this impasse by dropping the story of an actual reduction in strength and relying solely on the argument of incomplete training. ‘In order to emphasise a later target date of 15th July, 1944, we should minimise the state of preparedness of the NEPTUNE forces by misleading the enemy about their state of training, organisation, equipment and their location.’31 For the rest the gap was to be closed by the arrival of American divisions during the operation. This, however, was no real solution, for ill-trained troops could be regarded as little better than no troops. Thus the policy of postponement militated at once against the diversion of the enemy’s attention from Normandy before the invasion and against the promotion of belief in a greater assault against the Pas de Calais after the invasion. To this unsolved problem we shall return.
FORTITUDE received the approval of the Combined Chiefs of Staff on 26th February, 1944. The draft Appendix ‘Y’ plan, which had been in the hands of the Joint Commanders for two months, was now relegated to the status of a staff study.
Finally it remains to be seen how command and control of the two major threats comprised in FORTITUDE were apportioned. The responsibility for co-ordinating and controlling the execution of the plan as a whole was retained by the Supreme Commander. On the other hand, it was considered that OVERLORD and its tactical cover plan, the threat to the Pas de Calais, were so interdependent that the commanders responsible for the detailed planning of the one should also have charge of the other.32 On these grounds the FORTITUDE directive of 26th February, 1944, laid down that: ‘The Allied Naval Commander, Expeditionary Force, the Commander-in-Chief, 21 Army Group and the Air Commander-in-Chief, Allied Expeditionary Air Force, will be responsible to the Supreme Commander for directing towards the Pas de Calais the threat created by the forces under their control and for concealing the state of readiness of these forces so as to indicate NEPTUNE D plus forty-five as the real target date. They will also be responsible for making preparations to continue the threat against the Pas de Calais.’33 When the bridgehead was established, these responsibilities would revert to SHAEF.
Conduct of the Norwegian campaign34 and control of the arrangements for reoccupying the abandoned sectors were retained by SHAEF, who also reserved to itself the handling of controlled leakage in respect of all three operations.