Anthony Blunt

Blunt was a professor of art history at the University of London, the director of the Courtauld Institute of Art and Surveyor of the Queen's Pictures. His 1967 monograph on the French Baroque painter Nicolas Poussin is still widely regarded as a watershed book in art history. His teaching text and reference work ''Art and Architecture in France 1500–1700'', first published in 1953, reached its fifth edition (in a version slightly revised by Richard Beresford) in 1999, at which time it was still considered the best account of the subject.
He was the "fourth man" of the Cambridge Five, a group of Cambridge-educated spies who worked for the Soviets between the 1930s and the 1950s. (Blunt was the fourth member of the group to be discovered.) The height of Blunt's espionage activity was during the Second World War, when he passed to the Soviets intelligence about ''Wehrmacht'' plans that the British government had decided to withhold. In 1964, after being offered immunity from prosecution, Blunt confessed to having been a spy for the Soviet Union. His confession—a secret for years— was revealed publicly by Prime Minister Margaret Thatcher in November 1979. He was stripped of his knighthood immediately thereafter and died a little over three years later. Provided by Wikipedia