MI5's decline in counter-espionage efficiency began in the 1930s. It was, to some extent, a victim of its own success. It was unable to break the ways of thinking it had evolved in the 1910s and 1920s. In particular, it was unable to adjust to the new methods of the Soviet intelligence services the
People's Commissariat for Internal Affairs (Russian: Наро́дный комиссариа́т вну́тренних дел,
tr. Naródnyy Komissariát Vnútrennikh Del) (NKVD) and
Main Intelligence Directorate (Russian: Гла́вное разве́дывательное управле́ние,
tr. Glavnoye Razvedyvatel'noye Upravleniye) (GRU). It continued to think in terms of agents who would attempt to gather information simply through observation or bribery, or to agitate within labour organisations and the armed services, while posing as ordinary citizens.
The NKVD, meanwhile, had evolved more sophisticated methods; it began to recruit agents from within the
upper classes, most notably from
Cambridge University, who were seen as a long-term investment. They succeeded in gaining positions within the government, and, in
Kim Philby's case, within British intelligence itself, from where they were able to provide the NKVD with sensitive information. The most successful of these agents;
Harold 'Kim' Philby,
Donald Maclean,
Guy Burgess,
Anthony Blunt, and
John Cairncross; went undetected until after the
Second World War, and were known as the
Cambridge Five.
MI5 experienced further failure during WW2. It was
chronically unprepared, both organisationally and in terms of resources, for the outbreak of war; and utterly unequal to the task which it was assigned: the large-scale internment of enemy aliens in an attempt to uncover enemy agents. The operation was poorly handled, and contributed to the near-collapse of the agency by 1940. One of the earliest actions of
Winston Churchill on coming to power in early 1940 was to sack the agency's long-term head,
Vernon Kell. He was replaced initially by the ineffective Brigadier A.W.A. Harker, as Acting Director General. Harker in turn was quickly replaced by
David Petrie, an
Secret Intelligence Service (SIS) man, with Harker remaining as his deputy.
With the ending of the
Battle of Britain, and the abandonment of invasion plans (correctly reported by both SIS and the
Bletchley Park Ultra project), the spy scare eased, and the internment policy was gradually reversed. This eased pressure on MI5, and allowed it to concentrate on its major wartime success, the so-called
'double-cross' system. This was a system based on an internal memo drafted by an MI5 officer in 1936, which criticised the long-standing policy of arresting and sending to trial all enemy agents discovered by MI5. Several had offered to defect to Britain when captured; before 1939, such requests were invariably turned down. The memo advocated attempting to 'turn' captured agents wherever possible, and use them to mislead enemy intelligence agencies. This suggestion was turned into a massive and well-tuned system of deception during the Second World War.
Beginning with the capture of an agent named
Arthur Owens, codenamed 'Snow', MI5 began to offer enemy agents the chance to avoid prosecution (and thus the possibility of the death penalty) if they would work as British
double-agents. Agents who agreed to this were supervised by MI5 in transmitting bogus 'intelligence' back to the German secret service, the
Abwehr. This necessitated a large-scale organisational effort, since the information had to appear valuable but actually be misleading. A high-level committee, the Wireless Board, was formed to provide this information. The day-to-day operation was delegated to a sub-committee, the
Twenty Committee (so called because the Roman numerals for twenty, XX, form a double cross).
The
Double-Cross System or
XX System was a
World War II counter-espionage and deception operation of the British Security Service (a civilian organisation usually referred to by its cover title
MI5).
Nazi agents in Britain – real and false – were captured, turned themselves in or simply announced themselves, and were then used by the British to broadcast mainly
disinformation to their Nazi controllers. Its operations were overseen by the Twenty Committee under the chairmanship of
John Cecil Masterman; the name of the committee comes from the number 20 in
Roman numerals: "XX" (i.e. a double cross).
The policy of MI5 during the war was initially to use the system for
counter-espionage. It was only later that its potential for deception purposes was realised. Of the agents from the German intelligence services,
Abwehr and
Sicherheitsdienst (SD), some were apprehended, while many of the agents who reached British shores turned themselves in to the authorities; others were apprehended after they made elementary mistakes during their operations. In addition, some were false agents who had tricked the Germans into believing they would spy for them if they helped them reach England (e.g.,
Treasure,
Fido). Later agents were instructed to contact agents who, unknown to the Abwehr, were controlled by the British. The Abwehr and SD sent agents over by parachute drop, submarine, or travel via neutral countries. The last route was most commonly used, with agents often impersonating refugees. After the war, it was discovered that all the agents Germany sent to Britain had given themselves up or had been captured, with the possible exception of one who committed suicide.
Following a July 1940 conference in
Kiel, the
Abwehr (German intelligence) began an espionage campaign against Britain involving intelligence gathering and sabotage. Spies were sent over from Europe in various ways; some parachuted or came off a submarine. Others entered the country on false passports or posing as refugees. Public perception in Britain was that the country was full of well trained German spies, who were deeply integrated into society. There was widespread "spy-mania", as Churchill put it. The truth was that between September and November 1940 fewer than twenty five agents arrived in the country; mostly of Eastern European extraction, they were badly trained and poorly motivated.
The agents were not difficult to spot and it became easier still when the German
Enigma machine encryption was broken. MI5, with advance warning of infiltration, had no trouble picking up almost all of the spies sent to the country. Writing in 1972,
John C. Masterman (who had, later in the war, headed the Twenty Committee) said that by 1941, MI5 "actively ran and controlled the German espionage system in [the United Kingdom]." It was not an idle boast; post-war records confirmed that none of the Abwehr agents, bar one who committed suicide, went unnoticed.
Once caught, the spies were deposited in the care of Lieutenant Colonel Robin Stephens at
Camp 020 (
Latchmere House, Richmond). After Stephens, a notorious and brilliant interrogator, had picked apart their life history, the agents were either spirited away (to be imprisoned or killed) or if judged acceptable, offered the chance to turn
double agent on the Germans.
Control of the new double agents fell to
Thomas Argyll Robertson (usually called Tar, from his initials), a charismatic MI5 agent. A
Scot and something of a playboy, Robertson had some early experience with double agents; just prior to the war he had been case officer to
Arthur Owens (code name Snow). Owens was an oddity and it became apparent that he was playing off the Germans and British, although to what end Robertson was unable to uncover. Robertson dispatched an ex-
RNAS officer called
Walter Dicketts (code name Celery) to neutral Lisbon in early 1941 to meet Owens' German spymaster,
Nikolaus Ritter from the Abwehr, to establish Owens'
bona fides. Unknown to Dicketts, Owens had betrayed him to the Germans before Dicketts entered Germany to be interrogated by experts from the Abwehr in Hamburg. Although Dicketts managed to get himself recruited as a German agent (while continuing to report to MI5), Owens claimed that Dicketts' survival meant he had been 'turned' by the Germans. When both agents returned to England, Robertson and his team spent countless hours trying to establish which agent was telling the truth. In the end Owens was interned for endangering Dicketts' life and for revealing the important information that his German radio transmitter was controlled by MI5. The whole affair resulted in the collapse of the entire Snow network comprising the double agents Owens, GW, Biscuit, Charlie, Summer and Celery. The experiment had not appeared to be a success but MI5 had learned lessons about how Abwehr operated and how double agents might be useful.
Robertson believed that turning German spies would have numerous benefits, disclosing what information Abwehr wanted and to mislead them as part of a
military deception. It would also discourage them from sending more agents, if they believed an operational network existed. Section B1A (a subordinate of B section, under
Guy Liddell) was formed and Robertson was put in charge of handling the double-agent program.
Robertson's first agents were not a success, Giraffe (George Graf) was never really used and Gander (Kurt Goose; MI5 had a penchant for amusingly relevant code names), had been sent to Britain with a radio that could only transmit and both were quickly decommissioned. The next two attempts were even more farcical;
Gösta Caroli
and
Wulf Schmidt (a Danish citizen) landed, via parachute, in September 1940. The two were genuine Nazis, had trained together and were friends. Caroli was coerced into turning double in return for Schmidt's life being spared, whilst Schmidt was told that Caroli had sold him out and in anger swapped sides.
Caroli quickly became a problem, he attempted to strangle his MI5 handler before making an escape, carrying a
canoe on a
motorcycle. He vaguely planned to row to Holland but came unstuck after falling off the bike in front of a policeman. He was eventually recaptured and judged too much trouble to be used. Schmidt was more of a success; codenamed 'Tate', he continued to contact Germany until May 1945. These eccentric spies made Robertson aware that handling double agents was going to be a difficult task.
The Double-Cross System was extraordinarily successful. A post-war analysis of German intelligence records found that of the 115 or so agents targeted against Britain during the war, all but one (who committed suicide) had been successfully identified and caught, with several 'turned' to become double agents. The system played a major part in the massive campaign of deception which preceded the
D-Day landings, designed to give the Germans a false impression of the location and timings of the landings (see
Operation Fortitude).
While the double-cross work dealt with enemy agents sent into Britain, a smaller-scale operation run by
Victor Rothschild targeted British citizens who wanted to help Germany. The '
Fifth Column' operation saw an MI5 officer,
Eric Roberts, masquerade as the
Gestapo's man in London, encouraging Nazi sympathisers to pass him information about people who would be willing to help Germany in the event of invasion. When his recruits began bringing in intelligence, he promised to pass that on to Berlin. The operation was deeply controversial within MI5, with opponents arguing that it amounted to entrapment. By the end of the war, Roberts had identified around 500 people. But MI5 decided not to prosecute, and instead covered the work up, even giving some of Roberts' recruits Nazi medals. They were never told the truth.
All foreigners entering the country were processed at the
London Reception Centre (LRC) at the
Royal Patriotic School, which was operated by MI5 subsection B1D; 30,000 were inspected at LRC. Captured enemy agents were taken to
Camp 020,
Latchmere House, for interrogation. This was commanded by Colonel Robin Stephens. There was a reserve camp, Camp 020R, at
Huntercombe, which was used mainly for long term detention of prisoners.
It is believed that two MI5 officers participated in 'a gentle interrogation' given to the senior Nazi
Heinrich Himmler after his arrest at a military checkpoint in the northern German village of Bremervörde in May 1945. Himmler subsequently killed himself during a medical examination by a British officer by means of a cyanide capsule that he had concealed in his mouth. One of the MI5 officers,
Sidney Henry Noakes of the
Intelligence Corps, was subsequently given permission to keep Himmler's
braces and the forged identity document that had led to his arrest.
Cambridge Five ..
Camouflage, Deception, Espionage, Intelligence ..
41-5-9 Enigma machine, code book captured ..
Espionage ..
German Intelligence ..
40-11-11 German Intelligence Coup ..
Hitler's Spies ..
Jones ..
Linguists & Y Stations ..
Operation Hillside - Cartography Unit ..
O.S.S. ..
Secret Service ..
Signals Decryption and Intelligence Analysis - WW1 ..
Turncoats for Nazis ..
