The Double-Cross System or XX System was a World War II counter-espionage and deception operation of the British Security Service. 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".
Wilhelm Franz Canaris was a German admiral and chief of the Abwehr, the German military intelligence service, from 1935 to 1944. He was initially a supporter of Adolf Hitler but by 1939 had turned against the regime.
Operation Fortitude was the code name for a World War II military deception employed by the Allied nations as part of an overall deception strategy during the build-up to the 1944 Normandy landings. Fortitude was divided into two sub-plans, North and South, with the aim of misleading the German High Command as to the location of the invasion.
Operation Bodyguard was the code name for a World War II deception plan employed by the Allied states before the 1944 invasion of northwest Europe. The plan was intended to mislead the German high command as to the time and place of the invasion. The plan contained several operations, and culminated in the tactical surprise over the Germans during the Normandy landings on 6 June 1944 (D-Day) and delayed German reinforcements to the region for some time afterwards.
Hugo Bleicher (1899–1982) was a senior non-commissioned officer of Nazi Germany's Abwehr who worked against French Resistance in German-occupied France.
Walter Friedrich Schellenberg was a German SS functionary during the Nazi era. He rose through the ranks of the SS, becoming one of the highest ranking men in the Sicherheitsdienst (SD) and eventually assumed the position as head of foreign intelligence for Nazi Germany following the abolition of the Abwehr in 1944.
Kurt Arthur Benno Student was a German general in the Luftwaffe during World War II. An early pioneer of airborne forces, Student was in overall command of developing a paratrooper force to be known as the Fallschirmjäger, and as the most senior member of the Fallschirmjäger, commanded it throughout the war. Student led the first major airborne attack in history, the Battle for The Hague, in May 1940. He also commanded the Fallschirmjägers in its last major airborne operation, the invasion of Crete in May 1941. The operation was a success despite German losses, and led the Allies to hasten the training and development of their own airborne units.
Operation Copperhead was a small military deception operation run by the British during the Second World War. It formed part of Operation Bodyguard, the cover plan for the invasion of Normandy in 1944, and was intended to mislead German intelligence as to the location of General Bernard Montgomery. The operation was conceived by Dudley Clarke in early 1944 after he watched the film Five Graves to Cairo. Following the war M. E. Clifton James wrote a book about the operation, I Was Monty's Double. It was later adapted into a film, with James in the lead role.
Sir John Cecil Masterman OBE was a noted academic, sportsman and author. His highest-profile role was as Vice-Chancellor of the University of Oxford, but he was also well known as chairman of the Twenty Committee, which during the Second World War ran the Double-Cross System, controlling double agents in Britain.
Josef Jakobs was a German spy and the last person to be executed at the Tower of London. He was captured shortly after parachuting into the United Kingdom during the Second World War. Convicted of espionage under the Treachery Act 1940, Jakobs was sentenced to death and subsequently shot by a military firing squad. He was not hanged because he was captured as an enemy combatant.
Operation Ironside was a Second World War military deception undertaken by the Allies in 1944. It formed part of Operation Bodyguard, a broad strategic deception plan instigated by the Allies throughout the year to help cover the June 1944 invasion of Normandy. Ironside supported the overall deception by suggesting to the Germans that the Allies would subsequently land along the Bay of Biscay. It complemented efforts to deceive the Germans into believing that the Allies would also land in southern France at this time. Bordeaux was an important port for the German war effort and had already been a target of commando raids two years earlier. Ironside intended to play on German fears of an invasion in the region, with the aim of tying down defensive forces following Operation Overlord in June 1944.
First United States Army Group was a fictitious Allied Army Group in World War II prior to D-Day, part of Operation Quicksilver, created to deceive the Germans about where the Allies would land in France. To attract Axis attention, prominent US general George S. Patton was placed in command of the fabricated formation.
The 80th Infantry (Reserve) Division was an infantry division of the British Army formed at the beginning of 1943, during the Second World War. For the twenty months that the division existed, it was a training formation. It was made responsible for providing final tactical and field training to soldiers who had already passed their initial training. After five additional weeks of training, the soldiers would be posted to fighting formations overseas. Notably, the division was used as a source of reinforcements for the 21st Army Group, which was fighting in Normandy. After all available troops left the United Kingdom for France, the division was disbanded.
The Abwehr was the German military intelligence service for the Reichswehr and Wehrmacht from 1920 to 1945. Although the Treaty of Versailles prohibited the Germans from establishing an intelligence organization of their own, they formed an espionage group in 1920 within the Ministry of Defence, calling it the Abwehr. The initial purpose of the Abwehr was defense against foreign espionage—an organizational role which later evolved considerably. Under General Kurt von Schleicher the individual military services' intelligence units were combined and, in 1929, centralized under his Ministry of Defense, forming the foundation for the more commonly understood manifestation of the Abwehr.
Nathalie "Lily" Sergueiew was a double agent who worked for MI5 during World War II under the codename "Treasure". She played a significant role in the Double-Cross System, particularly by deceiving the Germans about the location of the D-Day landings.
R Force was a British deception force during World War II that consisted of armoured vehicles, field engineers and a wireless unit. During Operation Fortitude it attempted to exaggerate the strength of Allied forces in Britain, and deceive German intelligence about Allied intentions. Later it performed a similar role during the fighting in Western Europe in 1944–45. It was commanded by Lieutenant Colonel David Strangeways.
Operation Royal Flush was a military deception employed by the Allied Nations during the Second World War as part of the strategic deception Operation Bodyguard. Royal Flush was a political deception which expanded on the efforts of another Bodyguard deception, Operation Graffham, by emphasising the threat to Norway. It also lent support to parts of Operation Zeppelin via subtle diplomatic overtures to Spain and Turkey. The idea was that information from these neutral countries would filter back to the Abwehr. Planned in April 1944 by Ronald Wingate, Royal Flush was executed throughout June by various Allied ambassadors to the neutral states. During implementation the plan was revised several times to be less extreme in its diplomatic demands. Information from neutral embassies was not well trusted by the Abwehr; as a result, Royal Flush had limited impact on German plans through 1944.
Johann-Nielsen Jebsen, nicknamed "Johnny", was an anti-Nazi German intelligence officer and British double agent during the Second World War. Jebsen recruited Dušan Popov to the Abwehr and through him later joined the Allied cause. Kidnapped from Lisbon by the Germans shortly before the Normandy landings, Jebsen was tortured in prison and spent time in a concentration camp before disappearing; he was presumed killed at the end of the war.
Walter Dicketts was a British double agent who was sent by MI5 into Nazi Germany in early 1941 to infiltrate the Abwehr and bring back information about any impending invasion of Britain.
Alphons Louis Eugene Timmerman was a Belgian ship's steward who became a spy for the German intelligence agency, the Abwehr, during the Second World War. He was captured by the security services upon his arrival in Britain in September 1941. MI5 officers posed as Timmerman in correspondence with the Abwehr in an attempt to deceive them as to the competence of the British security services. This attempt was unsuccessful as German intelligence officers failed to spot deliberate mistakes in the letters, but did help to disprove the Abwehr's previously good reputation for intelligence work. Timmerman admitted to being a spy and was executed at Wandsworth Prison in 1942.
