circa 1975: Four members of the 'Cambridge Five', graduates of Trinity College, Cambridge, who passed information from British Intelligence to the Soviet Union in the 1940s and 1950s. Clockwise from top left, Anthony Blunt (1907 - 1983), Donald Duart Maclean (1913 - 1983), Kim Philby (1912 - 1988) and Guy Burgess (1911 - 1963). (Photo by Keystone/Hulton Archive/Getty Images)
