The Cambridge Five
was a ring of British
spies who passed information to the Soviet Union
during World War II
. The five consisted of Kim Philby
, Donald Maclean, Guy Burgess, Anthony Blunt
, and John Cairncross
Cairncross's role in the spy ring was a mystery for decades. During this time, there was a great deal of speculation that Victor Rothschild was the fifth man. Indeed, speculation continues that Cairncross was a sixth man.