Harold Adrian Russell "Kim" Philby (1912 -- 1988) was a high-ranking member of British intelligence who worked as a double agent before defecting to the Soviet Union in 1963. Codenamed 'Stanley', he served as both an NKVD and KGB operative.
In 1963, Philby was revealed to be a member of the spy ring now known as the Cambridge Five, the other members of which were Donald Maclean, Guy Burgess, Anthony Blunt and possibly John Cairncross. Of the five, Philby is believed to have been most successful in providing secret information to the Soviet Union. His activities were moderated only by Joseph Stalin's fears that he was secretly on Britain's side.
Philby claimed publicly in January 1988 that he did not regret his decisions and that he missed nothing about England except some friends, Colman's mustard and Lea & Perrin's Worcestershire sauce. Philby died of heart failure in Moscow in 1988. He was awarded a hero's funeral and numerous medals by the USSR.
Graham Greene, Philby's close friend, wrote the screenplay for the 1949 film The Third Man using Philby as the model for Harry Lime. The character was played by Orson Welles.
John le Carré (David Cornwell) depicts Philby as Bill Haydon, the upper-class traitor in the 1974 novel Tinker Tailor Soldier Spy. The novel has been adapted as a 1979 TV series, a 2011 film, and radio dramatisations in 1988 and 2009. In real life, Philby had ended le Carré's intelligence officer career by betraying him to the Russians.
