The Cambridge Five

The brightest British minds who swapped the biggest state secrets

The Cambridge Five were the most notorious of all the spies who worked for the Soviet Union. This British quintet were exceptional for a number of reasons: while they worked independently, they knew the identities of one another; they spied at a critical time (during the Second World War and the early Cold War); the content of their espionage complemented each other, as each worked in different parts of the government. And the amount of information they provided was unsurpassed.

The five were recruited while students at the University of Cambridge in the 1930s and each would go on to have successful dual careers as British civil servants and Soviet spies. Kim Philby (1912–88) spent most of his career working for the British intelligence agency MI6, including a period as head of Soviet counterespionage and as MI6 liaison officer to the CIA in Washington DC. Donald Maclean (1913–83) had a successful career in the Foreign Office, working on atomic and military matters. Guy Burgess (1911–63) worked briefly for MI6, but also spent some time in the Foreign Office, working in London on propaganda, and then in the British Embassy in Washington.

Anthony Blunt (1907–83) spent most of the Second World War in MI5, where he passed on details of the interception of German Enigma codes and of German spying activities in the UK. The last member was John Cairncross (1913–95), who spent a year during the war at the famous codebreaking facility Bletchley Park, also working on German codes.

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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)
c1975, 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, Donald Duart Maclean, Kim Philby and Guy Burgess. (Photo by Keystone/Hulton Archive/Getty Images)

The five passed across a staggering amount of material, primarily in the form of actual documents or photographs of documents. So good was their information that the Soviets initially did not believe they were genuine. Maclean and Burgess ended up defecting to the Soviet Union in 1951, as did Philby in 1963. Blunt, a third cousin of Elizabeth II’s mother, was knighted in 1956. He secretly confessed to MI5 in the early 1960s and was publicly revealed in 1979 by then-prime minister Margaret Thatcher and stripped of his knighthood. Cairncross left the civil service after the war and spent his career outside government. He finally revealed his role in 1979, before retiring and publishing his memoirs.

1958: Sir Anthony Blunt (1907 - 1983) and Princess Margaret (1930 - 2002) examining a detail on an antique trunk in the Lee Collection of the Courtauld Institute of Art where Anthony Blunt is director (1947 to 1974). (Photo by Edward Miller/Keystone/Getty Images)
Sir Anthony Blunt and Princess Margaret, c1958. (Photo by Edward Miller/Keystone/Getty Images)

The Rosenbergs

The married couple caught out by a close relative’s testimony

The Rosenbergs were a married couple, Julius (1918–53) and Ethel (1915–53). They gained notoriety not so much for the value or quantity of the intelligence they provided to the USSR, but because they were executed in the United States for committing espionage.

Julius Rosenberg joined the US army in 1940, but was discharged a few years later when his membership of the Communist party became known. In the meantime, he had been recruited by Soviet intelligence. His handler, Alexander Feklisov, claimed that Rosenberg had passed across several thousand pages of documents, but that these did not warrant execution. The high point of the Rosenbergs’ career was yet to come.

Ethel’s brother was a technician called David Greenglass. In 1943 he was posted to the Manhattan Project, the super-secret wartime atomic bomb programme. Also a member of the Communist party, Greenglass was recruited by the Rosenbergs and used his new position to pass detailed designs to the Soviets. Greenglass recruited another individual, Harry Gold, who would act as a courier for the infamous atomic spy Klaus Fuchs.

Condemned spy Julius Rosenberg sits manacled in a United States Marshal's van en route to the Federal House of Detention, New York. His wife Ethel sits behind him. Despite pleas for clemency the pair were executed. (Photo by © Hulton-Deutsch Collection/CORBIS/Corbis via Getty Images)
Ethel and Julius Rosenberg. Despite pleas for clemency, the pair were executed for espionage. (Photo by © Hulton-Deutsch Collection/CORBIS/Corbis via Getty Images)

In 1950 Fuchs confessed to British authorities and, in the ensuing investigation, the FBI discovered the identities of Gold, Greenglass and the Rosenbergs. As part of a deal to reduce his own sentence (he served under 10 years), Greenglass provided details on his sister and brother-in-law’s activities. As a result, both were convicted and subsequently executed in 1953.

The case continued to cause interest because Greenglass’s testimony was concealed from the public and the evidence that Ethel had spied was debatable at best.

It was also not proven that Julius had been involved with atomic espionage. When Greenglass’s witness testimony from 1951 was finally released in July 2015, it revealed that he never mentioned Ethel Rosenberg’s involvement in the delivery of atomic secrets to Soviet operatives.

John Vassall

The civil servant blackmailed into working for the KGB

John Vassall spent much of the Second World War as a photographer in Britain’s Royal Air Force. After the war, he joined the Admiralty as a clerk, an administrative position that enabled access to a range of documentation. In 1952, he was given a position at the British embassy in Moscow, responsible to the naval attaché. Vassall found his position difficult, objecting to what he considered the snobbish culture of the diplomatic circuit.

He had a greater problem though: Vassall was a homosexual at a time when it was illegal, both in Britain and the Soviet Union. Had this fact become known, he would have lost not only his security clearance but also his job. In his memoir, published many years later, Vassall wrote about the loneliness he felt in Moscow. Soviet intelligence recruiters, skilled in spotting vulnerable targets, saw an opportunity. In 1954, Vassall was invited to a party, given copious amounts of alcohol and voluntarily engaged in sexual activities with a number of men. Unknown to him, he was the victim of a classic Soviet honeytrap: shortly afterwards, Vassall was shown incriminating photographs and blackmailed into working for Soviet intelligence.

He was not an ideological convert and had no love for the Soviet Union but, backed into a corner, he began to provide the Soviets with a variety of intelligence on British military matters. He returned to London in 1956 and continued to pass intelligence to the KGB. He was unmasked in 1961, with the defection of the KGB’s Anatoliy Golitsyn to the west, and was arrested the following year. He confessed and eventually served 10 years of an 18-year sentence. He worked in London after his release and died in 1996 after suffering a heart attack on a bus.

Ted Hall

The math prodigy who turned Soviet collaborator

Ted Hall (1925–99) was a child prodigy in mathematics, graduating from Harvard University in 1944 at the tender age of 18. He had already accepted a position at Los Alamos and began work on the designs of the two atomic bombs that would be dropped on Hiroshima and Nagasaki. There is some debate as to quite why Hall decided to volunteer for Soviet intelligence: shortly before his death in 1999, he conceded that he did it out of a desire for the US not to have a monopoly on atomic weapons, but this does not satisfactorily explain why he chose the Soviets to be his confessor.

Hall worked on the Manhattan Project for just two years, but in that time provided a wealth of data on the atomic bomb and, perhaps more importantly, details on the early scientific investigations into the far more destructive hydrogen bomb.

As part of the FBI investigation into Klaus Fuchs, Hall was questioned, but no further action was taken. His precise role did not become public until 1995 when the British and US governments released details of the Venona Project, the code name given to the breaking of wartime Soviet ciphers. In these documents, Hall’s espionage was revealed, as was the decision in the early 1950s not to prosecute him as the necessity to keep the Venona Project secret was greater. He spent most of his subsequent career working on non-secret matters at the University of Cambridge.

Aldrich Ames

The careless CIA operative who aroused much suspicion

While the first batch of Soviet spies worked for ideological reasons, that motivation became less convincing as the Cold War progressed. Instead the Soviets turned towards other human frailties for motivation and none would be more appealing than cold, hard cash. Aldrich Ames (born in 1941) did a number of odd jobs for the CIA (including painter and clerical worker) before he joined the agency proper in the late 1960s as an operational officer. One of his first postings was to Turkey, where he worked on recruiting Soviet intelligence officers. This experience led to a career-long involvement with Soviet espionage, working mainly at headquarters in Langley, Virginia, but with a further posting to Mexico City and New York.

ARCHIVES : C.I.A MOLE, ALDRICH AMES (Photo by Jeffrey Markowitz/Sygma via Getty Images)
Aldrich Ames did a number of odd jobs for the CIA. (Photo by Jeffrey Markowitz/Sygma via Getty Images)

Despite reports of excess drinking and adultery, Ames continued to be promoted within the CIA. In 1983 he was given an exceptionally sensitive role working on Soviet counterespionage, a task that provided him with details of all CIA operations and spies working against the USSR. That year he filed for divorce, a process that would be extremely costly. His position in the CIA legitimately enabled him to meet Soviet intelligence officers and, during one of these meetings in 1985,

Ames volunteered to spy in exchange for money. Before long, US spies working against the Soviet Union began to vanish, yet despite a number of internal investigations and lie detector tests, Ames remained above suspicion. His role in the CIA meant that he could continue to meet Soviet intelligence officers. For each encounter, he was paid handsomely by the Soviets. Ames’ treachery was eventually uncovered in 1994, a feat that had begun with the simple fact that Ames’ spending far outweighed his income. He was convicted of espionage and sentenced to life in prison. The intelligence provided by Ames did irrevocable damage to US (and allied) intelligence efforts and led to many deaths.


This article first appeared in BBC History Magazine's 'Spies & Espionage' special edition