SINCE THEIR FIRST MEETING IN January 1941, it had been the ambition of the Twenty Committee to use the double agents of B1a in a major deception against the Germans. Now, with Allied aerial supremacy limiting German reconnaissance flights over Britain, the most important and successful means of delivering Fortitude directly to German High Command was through the agents under Twenty’s control. This was exactly the sort of show that had been envisaged by Masterman in early 1941, for which the double agents had been built up and made to appear plausible to their German employers. The committee was quite prepared to blow all its agents on one big show and Overlord fitted the bill perfectly.
The first inkling that the spies would be used in the invasion deception came in the late summer of 1943. At a meeting of the Twenty Committee’s parent body — the W Board — in September 1943, Johnny Bevan was co-opted as a member. Still at the planning stages of the invasion cover plan, Bevan asked MI5 and SIS representatives if all the German agents operating in the United Kingdom were under their control. Given that no other networks had been picked up by the RSS through postal censorship or from discussions intercepted by ISOS, they concluded there was still no evidence of any other clandestine German activities.
After this meeting, towards the end of1943, there followed a review of all the double cross cases, after which the W Board cherry-picked those it believed could be used to support Bodyguard. From the continual daily monitoring of ISOS intercepts, B1a were able to report that, in German eyes, the three strongest cases were Tricycle, Garbo and a relative newcomer to XX work called Brutus, who will be fully introduced later. In the second line were Tate, Mullet, Mutt and Jeff, and three female agents: Gelatine, Bronx, and a recent addition to the team codenamed Treasure. Taking that as their running order, at the W Board meeting on 21 January 1944 the members authorized the Twenty Committee to go all out on the deception plan for Overlord, even if it meant sacrificing all the agents.
Having made this decision, the Twenty Committee took more of a back seat in the invasion deception. It was decided that SHAEF Ops. B would be the approving authority for deception material and that a representative from That body should sit on the Twenty Committee. Since his secondment to Ops. B in April 1943 from Army Intelligence, Lieutenant Colonel Roger Fleetwood-Hesketh, working under Jervis-Read, had become the linkman between COSSAC and ‘Special Means’. Through the auspices of the LCS, Hesketh had been made aware of the existence and availability of Bla’s double agents. Under COSSAC, approval for ‘special means’ traffic had been given by a weekly sub-committee known as Twist. Chaired by Bevan, these meetings were used to allocate leakages and other ‘special means’ information to the best channel for it to reach the enemy. Anticipating the increased workload prior to D-Day, Bevan decided it was best to cut out the middle-man and shut down Twist in favour of direct meetings between Ops. B and Bla. To achieve this, an MI5 officer from Bla, Major Christopher Harmer, was posted to Ops. B to act as a liaison between the two organizations.
From that point on the coordination of the double agents used for D-Day happened extremely informally, with the majority of decisions made after direct conversation between Hesketh and the case officers.1 Hesketh was based in Eisenhower’s headquarters at Norfolk House, 31 St James’s Square, just a short walk along King Street to MI5’s headquarters at 58 St James’s Street. Case officers like Tommy Harris (for Garbo) and Hugh Astor (for Brutus) would go over to Hesketh at Norfolk House and thrash out the details of messages to be sent by their particular agent. In turn, Hesketh would often visit the London Controlling Section’s offices at Storey’s Gate on the other side of St James’s Park. There he would explain developments to Harold Peteval, who dealt with ‘special means’ traffic on behalf of Johnny Bevan. As the Fortitude South plan developed, Hesketh also had to consult with the deception officer, Colonel Strangeways, before approving anything relating to Twenty-First Army Group. Hesketh therefore had his brother Cuthbert seconded to Ops. B and used him more or less daily as a despatch rider between Norfolk House and Montgomery’s Twenty-First Army Group HQ at Southwick Park near Southampton.
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