The Cambridge Spy Ring was a group of five British double agents who worked for the USSR’s intelligence services, the NKVD, from 1934 until the eventual uncovering of the conspiracy in the early 1950s. The Cambridge Five were so named as their members – Donald Maclean, Guy Burgess, Kim Philby, Anthony Blunt and John Cairncross – had all been recruited whilst studying at Cambridge University. They proved highly effective double agents and their discovery severely damaged the reputation of the British intelligence services.
The first supposedly to be ‘turned’ was Philby, who was recruited in June 1934 by Arnold Deutsch, a Soviet agent posing as a visiting researcher at University College London. Philby then recommended Donald Maclean and Guy Burgess, who were both recruited in 1935 and told to pursue careers in diplomacy to maximise their utility as spies.
The story surrounding Anthony Blunt’s recruitment is less clear. According to some accounts, Blunt had been recruited by Soviet intelligence in early 1934 after a visit to Moscow in 1933. He had then suggested Philby as a potential recruit and continued to work as a talent-spotter in Cambridge, where he also suggested Maclean and Burgess, or ratified Philby’s suggestion. However, Blunt wrote in his memoirs that he was convinced to spy for the USSR by Burgess, his close friend, at some point after Burgess and his contemporaries had already been recruited. This date is suggested to be January 1937, when he was introduced to Arnold Deutsch, the same officer who had recruited Burgess and Philby. All accounts do agree that, by 1937, Blunt was a Soviet spy, and he was responsible for the recruitment of Cairncross in 1938, the final member of the Five.
Regardless of the precise timings or mechanisms of their recruitment, they all had a shared motivation in strong anti-fascist beliefs. Philby came to the attention of Soviet recruiters when he spent time in Austria aiding Jewish refugees from Nazi Germany and protesting against the fascism of the Austrian Chancellor Dolfuss. Blunt said in his memoir he started spying because he “realised that one could no longer stand aside. The issue of Fascism, as posed by the advent to power of Hitler and later by the Spanish Civil War, became…urgent.”
However, all five were more than simply anti-fascists. They were all committed communists and believed firmly in Marxism-Leninism as the best political and economic system. Philby, Burgess and Maclean were all Communist Party members in the early 1930s before deciding to spy for the Soviets, while Blunt and Cairncross were closely associated with the party too. Their interests in Communism and anti-fascism aligned as they believed that supporting the USSR was the best way to act against the tide of fascism which was then sweeping 1930s Europe.
The Cambridge Five all successfully rose to positions of prominence within the British establishment, allowing them access to classified material which was shared with the Soviets. Philby was a senior officer in MI6, Burgess and Maclean senior diplomats, Blunt a member of MI5 and Cairncross a senior civil servant. The Cambridge Five proved highly effective, sharing 17,000 classified documents with the NKVD. The majority of their most important work was done during WWII, as they passed information known only to British and US intelligence along to the USSR. While the US and UK were formally allied with the USSR, there was still deep mistrust between them: the Cambridge Five thus disclosed intelligence to the USSR that the UK and US were not willing to divulge.
Cairncross was perhaps the most low-profile of the group, and to this day is less well-known than his more notorious counterparts. However, he was the most prolific of the Five, sending 5,800 documents to the Soviets, many of which were high value. He shared information about Operation Citadel, the last offensive launched by Nazi Germany in Russia, and revealed post-war British and American plans for NATO. He maintained that he was never a Communist nor a traitor, and that he was acting to make sure the USSR, the UK’s wartime ally, received the necessary intelligence to win the war which he believed was being withheld by a ‘right wing clique’ within the wartime government. This claim is somewhat doubtful as his Soviet handler, Yuri Modin, who later defected to the West, maintained that Cairncross continued to pass on intelligence until at least 1952, long after the end of the war.
Maclean continued to work for the USSR after the war too, passing on information from 1944 to 1948 on the sharing of nuclear secrets between Canada, the UK and the US from his position as the chair of the Combined Policy Committee. Burgess, who served on the inter-allied board for the Korean War, passing on strategic information about American operations, whilst Philby, well-placed as the head of MI6 in the US and First Secretary to the British Embassy, protected fellow Soviet spies and passed on classified MI6 internal documents.
Despite the volume and classified nature of documents they received, the USSR discarded or did not read ‘about half’, as they were doubtful of their accuracy and veracity. They were particularly dubious with information from Kim Philby, as they could not see how a formerly outspoken Communist (as Philby was) would have been able to reach such a senior position within the intelligence service. The NKVD concluded, therefore, that the only way Philby could reach such a position was if he were actually a British spy, a ‘triple agent’, and was passing on selected, and potentially falsified, documents. In truth, the NKVD’s suspicions, whilst incorrect, were well-founded. Philby was suspected due to his past and MI6 reportedly had clear evidence that he was a spy. That they failed to take action, Philby maintained, was due to their incompetence.
The conspiracy was initially uncovered in May 1951. Philby was stationed in the British Embassy in Washington DC and became aware that British intelligence was searching for a mole who had worked within the Embassy during the war, codenamed ‘Homer’ by the Soviets. The prime suspect was Donald Maclean. He asked Burgess, also currently stationed in the Embassy, to get to London and warn Maclean to flee to Moscow and defect. What had not been planned was Burgess fleeing too, as he joined Maclean on his flight to Moscow. The disappearance of the two made headlines, and though it was not known they had defected to the USSR, it was widely suspected, though these suspicions were not confirmed until 1956.
Given the suspicion Maclean was under at the time of his disappearance, it was obvious he must have been informed. Since Burgess did not rank highly enough to be privy to this information, he must have been tipped off himself by a more senior officer. Kim Philby was suspected, given his close relationship with Burgess. He thus resigned from MI6 two months later.
The disappearance and presumed defection of Burgess and Maclean severely damaged US-UK relations, especially with regards to intelligence sharing. At least three Soviet spies, in Burgess, Maclean, and the man who tipped them off, were known to have operated within Britain’s US Embassy, with at least one a senior figure. The US believed they could no longer trust the UK’s intelligence agencies given this serious breach in security. A telegram from the British Embassy to the Foreign Office said they had been told by CIA and State Department officials that they were ‘highly disturbed’ by the disappearance of the two, and ‘the incident has severely shaken the State Department’s confidence in the integrity of officials of the Foreign Office,’ especially given that Burgess had been allowed to continue at the Embassy to that point despite his notoriety for drunkenness and bad behaviour.
Speculation continued around Philby until 1955, where he gave a press conference in which he stated, ‘I have never been a Communist.’ In November 1955, he was officially exonerated by Harold MacMillan, at the time the foreign secretary and the future Prime Minister from 1957 to 1963. Philby then went on to work for The Observer and The Economist in Beirut as a Middle East correspondent, and resumed MI6 work in 1956 in secret, which allowed him to simultaneously resume his operations as a Soviet spy.
Anatoly Golitsyn, a former Soviet agent, defected to Britain in 1961, however, and confirmed the long-held suspicion that Philby was the third man. He also informed British intelligence that Philby was the third of a ring of five, although he only knew the identities of Philby, Burgess and Maclean, not Blunt or Cairncross. Despite this information, Philby continued working as a double agent throughout 1962, outside the jurisdiction of the British government, as Lebanon had no extradition treaty with the UK. He finally fled to Moscow in January 1963, and his defection was confirmed in July of that year.
The defection of Philby in 1963 was one of a series of scandals that undermined trust in MacMillan’s Conservative government, not least because he had been under suspicion as a Soviet operative from 1951 onwards. It was particularly damaging to MacMillan, having exonerated Philby personally in 1955 in the House of Commons.
Anthony Blunt and John Cairncross were both questioned in the aftermath of Philby’s defection, with both striking deals for anonymity and immunity from prosecution in exchange for confessions and information in 1964. Blunt was eventually uncovered by Andrew Boyle in his book, Climate of Treason, in 1979, and Margaret Thatcher confirmed the book’s revelations in the House of Commons later that year. Cairncross confessed publicly to the journalist Barrie Penrose that same year. The identities of the Cambridge Five were confirmed absolutely by the 1994 publication by Yuri Modin of My Five Cambridge Friends: Burgess, Maclean, Philby, Blunt, and Cairncross.
The failure of the British government to realise that the very highest levels of their intelligence services had been infiltrated was a chilling enough indictment – that they were all from Cambridge, a bastion of the British establishment, accentuated this perception of rot, amateurism and staggering complacency at the heart of the British government.
Boyle, A., 1979. Climate of Treason. Hutchinson.
Davenport-Hines, R., 2018. Enemies Within: Communists, the Cambridge Spies and the Making of Modern Britain. Collins.
Lownie, A., 2015. Stalin’s Englishman: The Lives of Guy Burgess. Hodder & Stoughton.
Modin, Y., 1994. My Five Cambridge Friends: Burgess, Maclean, Philby, Blunt, and Cairncross. Farrar, Strous & Giroux.