The Double-Cross System or XX System was a World War II counter-espionage and deception operation of the British Security Service (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".
MI5, officially the Security Service, is the United Kingdom's domestic counter-intelligence and security agency and is part of its intelligence machinery alongside the Secret Intelligence Service (MI6), Government Communications Headquarters (GCHQ), and Defence Intelligence (DI). MI5 is directed by the Joint Intelligence Committee (JIC), and the service is bound by the Security Service Act 1989. The service is directed to protect British parliamentary democracy and economic interests and to counter terrorism and espionage within the United Kingdom (UK).
Captain Sir Mansfield George Smith-Cumming was a British naval officer who served as the first chief of the Secret Intelligence Service (SIS).
Dame Stella Rimington is a British author and former Director General of MI5, a position she held from 1992 to 1996. She was the first female DG of MI5, and the first DG whose name was publicised on appointment. In 1993, Rimington became the first DG of MI5 to pose openly for cameras at the launch of a brochure outlining the organisation's activities.
M is a codename held by a fictional character in Ian Fleming's James Bond book and film series; the character is the Chief of the Secret Intelligence Service for the agency known as MI6. Fleming based the character on a number of people he knew who commanded sections of British intelligence. M has appeared in the novels by Fleming and seven continuation authors, as well as appearing in twenty-four films. In the Eon Productions series of films, M has been portrayed by four actors: Bernard Lee, Robert Brown, Judi Dench and Ralph Fiennes, the incumbent; in the two independent productions, M was played by John Huston, David Niven and Edward Fox.
Nathaniel Mayer Victor Rothschild, 3rd Baron Rothschild,, was a British scientist, intelligence officer during World War II, and later a senior executive with Royal Dutch Shell and N M Rothschild & Sons, and an advisor to the Edward Heath and Margaret Thatcher governments of the UK. He was a member of the prominent Rothschild family.
Rupert William Simon Allason is a British former Conservative Party politician and author. He was the Member of Parliament (MP) for Torbay in Devon, from 1987 to 1997. He writes books and articles on the subject of espionage under the pen name Nigel West.
Sir Roger Henry Hollis was a British intelligence officer who served with MI5 from 1938 to 1965. He was Director General of MI5 from 1956 to 1965.
William Melville was an Irish law enforcement officer and the first chief of the British Secret Service Bureau.
Henry Chapman Pincher was an English journalist, historian and novelist whose writing mainly focused on espionage and related matters, after some early books on scientific subjects.
Anna Nikolayevna Wolkova, sometimes known as Anna de Wolkoff, was a White Russian émigrée, and secretary of The Right Club, which was opposed to Britain's involvement in World War II.
Gordon Thomas was a British investigative journalist and author, notably on topics of secret intelligence. Thomas was the author of 53 books published worldwide including The Pope's Jews, Secret Wars, and Gideon's Spies, with sales exceeding 45 million copies. Thomas got the scoop on the nationalisation of the Suez Canal for the Daily Express in 1956. He was a cousin of the poet Dylan Thomas.
Guy Maynard Liddell, CB, CBE, MC was a British intelligence officer.
Henry Graham Pollard was a British bookseller and bibliographer.
The Defence of the Realm: The Authorized History of MI5, published in the United States as Defend the Realm, is an authorised history of the British Security Service (MI5), written by historian Christopher Andrew. Andrew was commissioned in December 2002 to write the history for MI5's 100th anniversary in 2009. He was given "virtually unrestricted access" to much of MI5's files, and "no restriction" on whatever conclusions he decided to draw from them. The book reported, amongst other things, that MI5 kept a file on Prime Minister Harold Wilson, as well as noting how many of Wilson's MP's were spying for the Soviet bloc. The book's title was derived from MI5's Latin motto, Regnum Defende. Historian Keith Jeffery was commissioned to write a similar authorised history of the Secret Intelligence Service (MI6) for release in 2010.
Charles Henry Maxwell Knight, known as Maxwell Knight, was a British spymaster, naturalist and broadcaster, reputedly a model for the James Bond character "M". He played major roles in surveillance of an early British Fascist party as well as the Communist Party of Great Britain.
The Secret Intelligence Service (SIS), commonly known as MI6, is the foreign intelligence service of the United Kingdom, tasked mainly with the covert overseas collection and analysis of human intelligence on foreign nationals in support of its Five Eyes partners. SIS is one of the British intelligence agencies and the Chief of the Secret Intelligence Service ("C") is directly accountable to the Foreign Secretary.
Eric Arthur Roberts was an MI5 agent during the Second World War under the alias Jack King. By posing as a Gestapo agent and infiltrating fascist groups in the UK, Roberts was able to prevent secret information from finding its way to Germany. Roberts continued to work for the British security services after the war, particularly in Vienna, but it was a time of great anxiety in the services because of the suspicions surrounding double agents such as the Cambridge spy ring.
Percy Eded Glading was an English communist and a co-founder of the Communist Party of Great Britain (CPGB). He was also a trade union activist, an author, and a spy for the Soviet Union against Britain, an activity for which he was convicted and imprisoned.
Andrew Cook is a British author, popular historian, television presenter/consultant and former British civil servant. He specializes in early 20th century espionage history. He has produced well-received biographies of Sidney Reilly and William Melville.
