Cambridge Five

The Cambridge Five was a ring of British spies who passed information to the Soviet Union during World War II, and up until the early 1950s. 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.

Sir Roger Hollis (at one time Director of MI5) was also alleged to have been the "fifth" man, notably by Arthur Martin (head of MI5's Soviet counter-intelligence section at the time), Peter Wright (former MI5 officer, author of Spycatcher, and at one time assigned to investigate Hollis) and Chapman Pincher (investigative journalist who produced several exposés of failures in British counter-intelligence).

They were originally known as the Cambridge Spy Ring because all known members of the ring were recruited at Trinity College, Cambridge, probably by Blunt (who was a Fellow there while the others were undergraduates).

The "Five" comes from KGB defector Anatoli Golitsin, who named Philby, Maclean and Burgess as part of a "Ring of Five" whose other two agents he did not know. However all three agents named by Golitsin had already defected to the USSR, and of all the information provided by Golitsin, the only item that was ever independently confirmed was the exposure of John Vassall. Vassall was a relatively low ranking spy whom some researchers believe may have been sacrificed to protect a more senior one. Golitsin also provided other information that is widely regarded as highly improbable, such as the claim that Harold Wilson (the Prime Minister of the United Kingdom) was a KGB agent. To this day Golitsin's reliability remains controversial, and as such there is little certainty of the actual number of agents in the Cambridge ring. To add to the confusion, when Blunt finally confessed he nominated several completely different people as among those he had recruited. Altogether, at least ten persons have been seriously indicated as possible members of Golitsin's "Ring of Five".