Kim Philby

 was a British spy. During the Cold War, he acted as a double agent for the Russians, and became a part of Tightrope, a group of spies on both sides who sought to ensure that the Cold War didn't become so hot that it escalated into open war. Realising that a third party, identified only as the Players, was attempting to provoke war, Philby enlisted the mysterious 'Doctor' to investigate the Players, the Doctor managing to smuggle key double agents out of the country and prevent a Player scheme to brainwash Harry S. Truman and Joseph Stalin to provoke open war. (PROSE: Endgame, History 101)

Behind the scenes

 * He was played by Michael Bilton in the 1987 film The Fourth Protocol.