About Kim Philby
Harold Adrian Russell "Kim" Philby was a British intelligence officer and a double agent for the Soviet Union. In 1963, he was revealed to be a member of the Cambridge Five, a spy ring that had divulged British secrets to the Soviets during World War II and in the early stages of the Cold War. Of the five, Philby is widely considered to have been the most successful in providing secret information to the Soviets.
Biography source:
Wikipedia
