XX-committee, a sub-committee of the W Board established by the British director of military intelligence in September 1940 to co-ordinate the dissemination of false information. It was set up in January 1941 to operate what was known as the double-cross system.
The aims of the XX, or Twenty, committee, were: to control, as far as possible, the German espionage system in the UK; to catch new
spies immediately they arrived; to acquire knowledge of the personalities, methods, codes, and ciphers of the
Abwehr which operated the spies, and to obtain information about German plans and intentions from the questions asked by it; to influence German plans by the answers sent to these questions; and, finally, to deceive the Germans about British plans and intentions. Though the first of such committees it was by no means the only one. In total 21 were formed in Europe, Africa, and the Middle East. For example, ‘A’ Force (see
deception) had what were known as Thirty Committees and there was a Forty Committee in Algiers which ran double agents furnished by the French Deuxième Bureau (see
France, 7).
The XX-committee was headed by an
MI5 officer, J. C. Masterman and one of its members was Lt-Cdr Ewen Montagu of the Admiralty's
Naval Intelligence Division. It assessed on a weekly basis what information could be passed to the Germans via their agents working under British control, and weighed the likely gains of doing so against the losses which could be caused by releasing it, a process likened by the chairman to handling dynamite.
MI5 had employed
double agents before the war. Every aspect of an agent's life, and what he transmitted either by wireless or by secret writing, was controlled by a sub-section of MI5's B Division, known as B.1A, headed by T. A. Robertson. This allotted a case officer, backed by technical and administrative staff, to each double agent. The case officer knew the agent's background and circumstances intimately, and made a careful assessment of his psychology.
One of MI5's earliest double agents, Arthur George Evans, codenamed SNOW, had been recruited by the Abwehr in the 1930s. Though he had to be imprisoned in March 1941 he did much useful work for MI5 before then. In April 1940 he tipped it off to the presence of an Abwehr control station aboard a ship in Norwegian waters. Signals from this ship in an Abwehr hand cipher were decrypted at
Bletchley Park, and it was on these, and later on
ULTRA intelligence, that the double-cross system relied to discover if the messages it was planting were still being accepted as genuine.
From 1940 onwards the Abwehr attempted to establish a number of agents in Britain but with the help of SNOW and other double agents they were all, with one exception, rounded up. The exception was Jan Ter Braak whose body was found in a Cambridge air-raid shelter in April 1941 after he had committed suicide, probably because he had run out of money.
MI5 had files on about 120 double agents, some of whom operated outside the UK. Those who did not come up to scratch for one reason or another—and they were the majority—were imprisoned and some were hanged. Altogether sixteen spies were executed in the UK during the war, two of whom were British.
Among the early recruits two of the most successful were a Dane called Wulf Schmidt (TATE) and a well-connected Yugoslav named
Dusko Popov (TRICYCLE). TATE, who was captured after landing by parachute in September 1940, became one of the XX-committee's most faithful wireless agents despite being a committed Nazi Party member. It was his messages about false minefields that, by the spring of 1945, kept 9,300 sq. km. (3,600 sq. mi.) of the Western Approaches (see
UK, 7(c)) clear of U-boats. The Germans also thought sufficiently highly of him to naturalize him by wireless so that he could receive the Iron Cross, First and Second Class (see
decorations), and he was also sent large sums of money (the whole double-cross system was almost entirely funded by the Abwehr). TRICYCLE had been recruited by the Abwehr in Belgrade and then sent to London to collect intelligence. He, and the network of notional agents he created, eventually became an important part of the XX-committee's
deception plans, as did two other important double agents: a Spaniard called
Juan Pujol (GARBO), who entered Britain in April 1942, and a Polish air force officer called
Roman Garby-Czerniawski (BRUTUS), who had been recruited by the Abwehr while heading the
interallié network in France. The latter arrived in the UK in October 1942.
By the time the XX-committee was established it appeared virtually certain that the complete German espionage network was under British control, but the double-cross system was always run on the assumption that there might be undetected spies at large who could check the truth of the controlled agents' messages. If there were any, they have never revealed themselves.
During 1941 the XX-committee implemented a number of deception plans and one of double-cross sabotage. These operations were small-scale affairs, early tests of the double-cross system, and most, for one reason or another, failed to work. However, some did, including ‘Plan Midas’ in which TRICYCLE successfully extracted £20,000-worth of US dollars from his German masters.
Another useful double agent whom the XX-committee ran was a London safe-breaker called Edward Chapman who had been recruited by the Abwehr while awaiting trial for burglary in the Channel Islands. He was parachuted into Cambridgeshire in December 1942 and promptly gave himself up. After a rigorous interrogation he was allowed to make contact with his Abwehr controller and was given the codename ZIGZAG. Chapman had been told to sabotage an aircraft factory at Hatfield. This was duly rigged and ZIGZAG returned in triumph to the Germans via Lisbon. In June 1944 he was again parachuted into the UK, this time to report, among other things, on the damage caused by the
V-weapons. Though he had retained the confidence of the Germans the British found him indiscreet, and his case was terminated in November 1944.
In the middle of 1942 the double-cross system began to be employed as part of larger scale deception plans associated with deceiving the Germans about the timing and place of the Normandy landings (see
OVERLORD), plans that came under the control of
SHAEF's Ops B when SHAEF was formed in early 1944. It was said that the XX-committee's main achievement during 1942 and 1943 was that, despite some narrow escapes, the double-cross system was preserved intact so that it could be employed in this fashion and GARBO, supported by BRUTUS and TATE, succeeded brilliantly in planting the necessary information. It was thought that the system was bound to be ‘blown’ by this grand deception, but in two instances at least the Germans chose, after the Normandy landings, to act on information received from the XX-committee: the final phase of the German U-boat campaign (the role of TATE in this has already been mentioned) and the targeting of V-weapons, where the Germans were persuaded to shorten the range so that many fell outside London.
The XX-committee has been criticized for being less professional than its counterpart in the Middle East, A-Force, and it was certainly helped in its task, wittingly or otherwise, by Abwehr officers who were either venal in the extreme or hostile to the Nazi regime. But its contribution to the success of the Normandy landings was undeniably an intelligence coup of the greatest strategic value.
Bibliography
Howard, M. , Strategic Deception (London, 1990).
Masterman, J. C. , The Double-Cross System in the War of 1939 to 1945 (New Haven, 1972).
