When once the composition of FUSAG had been determined and locations fixed, the controlled agents could safely proceed with the task of building up the fictitious Order of Battle and of preparing for the false move to concentration. As with FORTITUDE NORTH, the disposition of the agents was the first consideration. It had for long been known that travel restrictions would be imposed in the embarkation areas. It was important that the movements of our observers should not be hampered by security measures, and it was to meet such a situation that Seven’s sub-agents had been recruited in December 1943, the idea being that they should be sent to places on the south and south-east coasts early in the New Year and so acquire a resident’s qualification before the visitors’ ban was imposed. Thus on 18th February1 GARBO informed the Germans that he was sending agent 7 (2) to Dover, 7 (4) to Brighton, 7 (5)2 to Exeter and 7 (7) to Harwich.
On 3rd April, Madrid showed itself to be favourably impressed by the progress which Seven’s new organisation was making: ‘I have taken note with great interest of what you have told me in your letters about the amplification of your network and the numerous messages which you have sent during the last few weeks have demonstrated to me that you have been absolutely right in your idea of nominating the old collaborators as sub-agents of their networks. In particular, the network of Seven appears to be the one which is giving the best results.’3
Meanwhile GARBO had been conducting tests upon the new recruits. Of 7 (2) he was able to report on 7th March: ‘Dover. I was able to confirm last Sunday the accuracy of the recent report sent by 7 (2) from Dover. I am, therefore, able to classify him in future as a good reporter.’4 Of 7 (4), in the same message: ‘With regard to the military report, it is completely accurate so that we can catalogue this collaborator as being good.’ Of 7 (7) on 13th April: ‘I consider this first report of this collaborator fairly good as he tries to get details from which one is able to appreciate the interest he takes in explaining what he has seen.’5
Apart from the members of the World Aryan Order, it was only thought necessary to make one agent become resident in the prohibited zone. The decision to send TATE to Kent was not taken until after the visitors’ ban had been imposed, but as the farmer for whom this agent worked in Hertfordshire had a friend, also a farmer, who lived near Ashford in Kent, and to whom TATE had been lent on several previous occasions, there was a good reason for exempting him from those restrictions on movement to which the general public were now bound to submit. Accordingly, on 25th May, TATE signalled: ‘Farmer friend at Wye is being called upon to do practically full-time Home Guard duties as he is an officer…. Owing to this my chief has agreed to lend me to his friend to help him out,’ and feeling, presumably, that exceptional times warranted exceptional risks, he added, ‘I am going to refuse to go unless I can get lodgings where I know I can take my transmitter.’6 Three days later: ‘Have found first-class lodgings with elderly couple in Wye. So far as I can see, ideal for radio purposes.’7 On 1st June he was able to tell the Germans that he had moved in.8 TATE’s activities in Kent were, of course, greatly restricted by the fact that he was a farm worker, a limitation which the enemy did not seem fully to appreciate, for on 31st May they asked him to investigate concentrations, moves and preparations in the areas of London, Southampton, Plymouth, Bristol and Oxford.9
Apart from GARBO and BRUTUS, for whom special roles were being prepared, the other agents were to work as freelances travelling about and visiting their friends to suit our convenience. We had, however, to remember that with the exception of TREASURE, who had a wireless transmitting set, and of PUPPET, who had the use of the Ministry of Supply bag to Lisbon, the imposition of the air-mail ban would put all the lesser agents out of action altogether for a considerable time. During May TREASURE herself was to become involved in a domestic crisis which would debar her from taking any further part in deception.10
Let us now see what the moves to concentration, real and false, entailed. The dividing line between the true American and British concentration areas coincided with the Southern and South-Eastern Command boundary. The American assault and early build-up forces were already collected in the South-West of England. Here, therefore, there would be nothing more than a number of comparatively local movements. In the British zone, however, several early build-up divisions, notably the Guards Armoured and the 11th Armoured Divisions, were due to move from Yorkshire to the south coast at the end of April and the beginning of May. Apart from FORTITUDE, therefore, this would be the only unmistakable indication of a move to concentration.
Let us next consider the false concentration. FUSAG would set up its headquarters at Wentworth near Ascot. There were to be two armies, one south and the other north of the Thames. The First Canadian Army, which was to command the forces in Kent and Sussex, was to remain in its real location at Leatherhead. Of its two corps, the 2nd Canadian Corps with its divisions under command was to move in reality during the second half of April from Sussex to Kent, while VIII Corps was to be falsely represented as transferring from Cheshire to Kent at the end of that month. Third Army, in command of the East Anglian forces, was to be shown as moving from Knutsford in Cheshire to Chelmsford, while of its two corps the XX, with three armoured divisions under command, in reality in Wiltshire, was to proceed fictitiously into Norfolk and Suffolk. Its other corps, the XII, which was to be shown in due course in Essex, with three divisions, two infantry and one armoured, under command, had not yet arrived from America.
Thus, two main false movements had to be shown, from Cheshire to Kent and from Wiltshire to East Anglia, to which must be added a smaller real movement of Canadian forces from Sussex to Kent. At the same time, we thought it inevitable that German Intercept would pick up the moves of British formations from Yorkshire to Hampshire and Sussex. We therefore decided that it would be unwise for the agents to remain completely silent about this, but in superimposing it upon the other two we hoped that the lesser transfer of forces from north to south would be eclipsed by the greater ones from north-west to south-east and from west to east. Over the activities of the Americans in the south-west a veil of silence was to be drawn.
The first step, so the Special Means Staff held, was to let the agents discover each formation in its existing location, for unless the Germans knew the points of departure as well as the places of arrival, the general direction of the move to concentration and the significance that we hoped they would attach to it would not be apparent.
In anticipation of this, TRICYCLE had already identified most of the formations in Yorkshire, having visited that county just before he left for Lisbon at the beginning of March. During the second week of April FREAK covered the ground a second time in order to fill in any gaps which had been left by his collaborator. By this time several of the American formations included in FUSAG had arrived and were stationed in Cheshire. FREAK therefore extended his journey westwards and was rewarded by the discovery of the Third United States Army at Knutsford with the 79th and 83rd Infantry Divisions under command.11 Meanwhile a visit by BRUTUS to Wiltshire revealed the presence of XX Corps and the 6th United States Armoured Division12 in that region, while GARBO found the 28th United States Infantry Division,13 which was to join VIII Corps in Kent when the latter came down from Cheshire, at Tenby in South Wales. Thus, by the time that the move was due to begin, the majority of the formations affected had been marked down in their old locations.
A diagram indicating the principal Allied troop movements reported to the enemy in May 1944
From this point the development of the operation, in so far as it concerned the double-cross agents, was governed by the Special Means plan of 6th May.14 The main provisions of this plan had been worked out about a fortnight before that date, an unofficial draft of the Joint Commanders’ Plan having been supplied to the Special Means Staff at SHAEF as early as 7th April. The Special Means Plan was therefore available for use before FUSAG’s move to concentration began on the 24th of that month. Appendix D of this Plan, a ‘Phased Programme for Identification and Grouping of Military Forces – 1st May to D Day’, provided the controlled agents and their case officers with a working programme of release dates for disclosing the identity, as well as the location and grouping, real or false, of every operational formation in the United Kingdom. The movement of each formation was assumed to extend over a period of about a week. Troop trains and road convoys were routed in the usual way, all timings being linked to the wireless deception programme. Within this framework the movements of the agents could be so arranged as to give them the desired opportunities for observation. Thus the false pattern could be systematically elaborated, day by day. Reports would flow in to the German Intelligence from agents stationed in all parts of the country, and each message would be found to confirm those that had gone before. And so at last the imaginary American Army Group in the South-East would gradually detach itself from the real British one in the South.