Kim Philby Part 2: I Really Must Be Going

After secretly committing himself to the cause of Communism and to serving the Soviet Union, Kim Philby worked as a reporter in the time preceding WWII. But once the War started, he decided to look for better ways to fight off Fascism and to gain access to the inner workings of his homeland. He'd been casting about for an invitation into British intelligence when fellow Trinity College alum Guy Burgess introduced him to the chief of staff of MI6 Section D's training school for propaganda, Marjorie Maxse. 

Once cleared to join British intelligence, Philby quickly rose through the ranks of MI6, and in doing so, granted Moscow unprecedented access to the inner workings of what would become one of their greatest enemies. If not for Philby's work as a spy for Russia, the Cold War likely would have ended very differently, for better or worse.