Cambridge Five: Britain's Soviet Spy Ring and Its Defections

The Cambridge Five were a ring of British men recruited by Soviet intelligence while at Cambridge University in the 1930s: Kim Philby, Guy Burgess, Donald Maclean, Anthony Blunt and John Cairncross. For nearly two decades they passed secrets from the Foreign Office, MI6, MI5 and wartime codebreaking to Moscow. The flight of Burgess and Maclean in May 1951 began their exposure, which unfolded over the following four decades.

Background: Cambridge in the 1930s

The early 1930s were years of economic depression and the rise of fascism. At Cambridge, as at other universities, many students saw the Soviet Union as the only firm opponent of Hitler and a model of a fairer society. Some joined the Communist Party or its student circles.

Soviet intelligence, then the NKVD, saw an opportunity. From 1934 its officer Arnold Deutsch, working in London under cover as an academic, recruited Philby, who suggested Maclean and Burgess; Burgess in turn helped bring in Blunt, and Cairncross, talent-spotted by Blunt, was recruited in 1937 through the communist James Klugmann. The recruits were told to break publicly with communism and pursue careers in the British establishment, where their background as upper-middle-class graduates would open doors.

The five spies

Kim Philby (1912–1988) joined the Secret Intelligence Service (MI6) in 1940 and rose to head its section dealing with Soviet counter-intelligence in 1944, an extraordinary position for a Soviet agent. In 1949 he became MI6’s liaison officer in Washington, with access to American intelligence.

Donald Maclean (1913–1983) entered the Foreign Office in 1935. As a diplomat in the British embassy in Washington from 1944 to 1948, he dealt with Anglo-American atomic co-operation and passed high-level political and nuclear policy information.

Guy Burgess (1911–1963) worked for the BBC, MI6 and the Foreign Office. Erratic and often drunk, he was nonetheless a prolific source of documents.

Anthony Blunt (1907–1983), an art historian, served in MI5 during the Second World War and passed information on its operations. After the war he became Surveyor of the King’s Pictures and director of the Courtauld Institute of Art.

John Cairncross (1913–1995) worked in the Foreign Office, the Cabinet Office and, in 1942–43, at the Bletchley Park codebreaking centre, from where he passed decrypted German material to Moscow.

What they passed

The volume of material was enormous. During the war the five supplied thousands of documents, from Foreign Office telegrams to intelligence assessments. Cairncross is credited with passing information from the British atomic programme’s early planning in 1941 and, from Bletchley Park, decrypted German signals on the Luftwaffe and German army before the Battle of Kursk in 1943.

Philby’s position allowed him to warn Moscow about Western operations against the Soviet Union. In 1945 he learned that Konstantin Volkov, a Soviet official in Istanbul, wanted to defect and was offering to name Soviet agents in Britain; Philby arranged to handle the case himself, and Volkov was seized by Soviet agents before he could be brought out. Maclean, in Washington and later in London, gave Moscow insight into Anglo-American atomic policy, the planning of NATO and, after 1950, British and American thinking about the Korean War.

Paradoxically, their Soviet handlers sometimes distrusted them. In the 1940s some officers in Moscow suspected that the flood of high-grade material was too good to be true and that the five might be British plants.

The 1951 defections

After the war, the American Venona project decrypted Soviet wartime cables. They showed that a source code-named HOMER had worked in the British embassy in Washington. By spring 1951 investigators had narrowed the suspects down to Maclean, and MI5 planned to interview him.

Philby, who followed the investigation from Washington, alerted Burgess, who had been sent home after a series of incidents. On 25 May 1951, Maclean’s 38th birthday, Burgess and Maclean drove to Southampton, crossed to France by ferry and vanished. Their disappearance caused a sensation. For years the government said little, and newspapers speculated about whether the two diplomats had been kidnapped, had fled for personal reasons or had gone to the Soviet Union. A government white paper finally confirmed the essentials in September 1955. They resurfaced in Moscow only in February 1956, when they appeared before Western journalists.

Life in the Soviet Union proved difficult for both. Burgess, homesick and drinking heavily, died in Moscow in 1963. Maclean learned Russian, worked as a specialist on British foreign policy and died there in 1983. His wife Melinda and their children joined him in 1953, travelling secretly from Switzerland.

Exposing the “third man”

Suspicion immediately fell on Philby, who had been close to Burgess. He was forced to resign from MI6 in 1951, but nothing could be proved. In November 1955 the Foreign Secretary, Harold Macmillan, told the House of Commons that there was no evidence Philby had betrayed his country, and Philby gave a confident press conference denying he was the “third man”.

He later worked in Beirut as a journalist. In January 1963, confronted with new evidence by his old MI6 friend Nicholas Elliott, he made a partial confession and then, on 23 January, disappeared; he surfaced in Moscow later that year. He died there in 1988.

Blunt confessed to MI5 in April 1964 in return for immunity, and the arrangement was kept secret for 15 years. After the journalist Andrew Boyle published The Climate of Treason, Margaret Thatcher confirmed in the Commons on 15 November 1979 that Blunt had been a Soviet agent. Cairncross confessed privately to MI5 in 1964 but was named publicly only in 1990, after the defector Oleg Gordievsky confirmed his role.

Consequences

The damage was serious. The spies passed thousands of documents, compromised Western operations and gave Moscow insight into British and American policy, including during the early Cold War and the Korean War. Philby’s betrayals are widely believed to have contributed to the failure of Western attempts to infiltrate agents into Albania from 1949 and to the capture of other agents.

The affair badly harmed relations between British and American intelligence and fed American suspicion of British security, already shaken by the Klaus Fuchs case. MI5 and MI6 spent years in damaging internal hunts for further moles, which poisoned trust within both services. In Britain the affair led to stricter vetting and long public debate about class, loyalty and the old-boy networks of the establishment.

Myths and facts

• Myth: the five were a tightly organised group. They knew of some of each other’s activities, but they were run largely as separate sources by their Soviet handlers.
• Myth: they were all exposed in 1951. Only Burgess and Maclean fled then; Philby escaped in 1963, Blunt was exposed in 1979 and Cairncross in 1990.
• Fact: none of the five was ever tried in a British court.

Timeline

• 1934: Arnold Deutsch begins recruiting Philby and others.
• 1944: Maclean is posted to the British embassy in Washington.
• 1951, 25 May: Burgess and Maclean flee Britain.
• 1955, November: Macmillan clears Philby in the Commons.
• 1956, February: Burgess and Maclean appear in Moscow.
• 1963, 23 January: Philby disappears from Beirut.
• 1964, April: Blunt confesses to MI5 in exchange for immunity.
• 1979, 15 November: Thatcher names Blunt in the Commons.
• 1990: Cairncross is publicly identified as the fifth man.

Why it matters

The Cambridge Five were among the most damaging spies of the twentieth century. Their story shaped Cold War intelligence, strained the Anglo-American alliance and left a lasting image of betrayal from within the British elite.