Three queer men—Guy Burgess, Donald Maclean, and Anthony Blunt—played key roles in an espionage scandal that rocked the British intelligence establishment in the 1950s. By passing British and American secrets to the Soviets during World War II and the early years of the Cold War, the Cambridge Spies likely changed the course of history.

Burgess, Maclean, Blunt, and their associate, Harold "Kim" Philby, came from upper-class backgrounds and received elite educations. They became friends at Cambridge University, where Blunt was a tutor and the other three were undergraduates. Burgess was a flamboyant gay man with an active sex life. He was an occasional lover of Blunt, and also reportedly had sexual liaisons with the bisexual Maclean and with Philby, who was otherwise heterosexual.

During the Depression, Cambridge was a hotbed of radical ideas. Many young intellectuals embraced Marxism and supported the Soviet Union, which they saw as a bulwark against encroaching fascism. Burgess, Maclean, Blunt, and Philby all made connections with the NKVD (precursor to the KGB) in the early 1930s, though it remains unclear who recruited whom.

Thanks to their family and school connections, the four men obtained various positions within the British foreign service and intelligence establishments. Burgess worked first for the BBC and then for the Secret Service, where he hired Philby. Although his job was of a sensitive nature, Burgess spent much of his time drinking and picking up men. After World War II, Philby was put in charge of a new anti-Communist counterespionage division. Blunt briefly worked for the counterintelligence service, but thereafter followed his passion for art.

Maclean moved up the ranks in the Foreign Service, and in 1944 landed a high-level position at the British embassy in Washington, D.C., which gave him access to information about the development of the atomic bomb. A tense and nervous man, Maclean found it increasingly difficult to manage what became a double life—although married, he engaged in indiscreet homosexual liaisons and spouted pro-Communist, anti-American rhetoric when drunk. Nevertheless, by 1950, he was head of Britain’s American Department in London.

By this time, Philby had become the top British intelligence officer in Washington. Despite Burgess’ indiscretions—the FBI described him as "a louche, foul-mouthed gay with a penchant for seducing hitchhikers"—he had garnered a position as Philby’s assistant. Before Burgess was dispatched to the United States, a state department official admonished him to avoid radicals, racial politics, and overt homosexual encounters. "In other words, I mustn’t make a pass at Paul Robeson?" Burgess replied, referring to America’s best-known black Communist.

In 1951, Philby learned that the FBI had discovered a spy within the British embassy. Maclean was a prime suspect, and Philby dispatched Burgess to London to warn him. Burgess embarked for England on the Queen Mary, having an affair with an American student during the passage.

On May 25, a Friday, a still-unidentified informant alerted Burgess that Maclean was to be questioned the following Monday. The two men fled to France, and from there defected to the Soviet Union. Maclean adapted to Soviet life, was joined by his wife and children, and served as an expert on Western economic policy. But Burgess missed the freedom and material benefits he had enjoyed in England. Although permitted to live with a male lover despite the Soviet ban on homosexuality, he continued drinking heavily and died at age 52.

With the abrupt departure of Burgess and Maclean, suspicion fell on Philby as the "third man" who had given Maclean the warning. He was relieved of his duties and sent back to London, but avoided censure until defecting Soviet agents fingered him a decade later. In 1963, he too fled to the Soviet Union, where he was given a high rank in the KGB and a position as a spy trainer.

Meanwhile, the search continued for the "fourth man" who had alerted Philby. In 1963, another former Cambridge associate, Michael Straight, told the FBI that Blunt had recruited him as a Soviet agent. By this time, Blunt had become one of Britain’s foremost art historians and curator of the royal family’s art collection; unlike Burgess and Maclean, he had always kept his homosexual affairs discreet. Blunt confessed to his role, but was given immunity and allowed to retain his positions, in part to spare the royal family embarrassment. In 1979, however, he was publicly exposed by Prime Minister Margaret Thatcher. Blunt was stripped of his knighthood and appointments, retreated from public life, and lived quietly with his lover until he died in 1983.

The defection of Burgess and McLean reinforced the association of homosexuality, Communism, and treason in the public mind, and sparked a witch-hunt for gay men in British foreign service and intelligence agencies. At the height of the McCarthy era, the case also had ramifications for homosexuals in the United States. The prohibition against gay men and lesbians holding federal government positions was not lifted until 1975.