Kim Philby: The British Spy Who Sold Secrets to Moscow

Harold Adrian Russell "Kim" Philby was one of the Cold War's most damaging intelligence operatives—not for the West, but against it. Born on 1 January 1912, the Cambridge-educated Philby rose through the ranks of Britain's MI6 to become head of the anti-Soviet section by 1944. Yet for nearly three decades, he worked exclusively for Soviet intelligence, delivering secrets that cost lives across the intelligence world.

Philby's recruitment into Soviet service came in 1934 while he was still a student at Trinity College, Cambridge. He was part of a broader network later known as the Cambridge Five—a spy ring that included Donald Maclean and Guy Burgess. Of all the members, Philby proved the most valuable asset the Soviets had ever cultivated inside Western intelligence.

After joining MI6 in 1940 as an instructor in clandestine propaganda, Philby positioned himself at the heart of British intelligence operations. By 1944, he headed the anti-Soviet section. Five years later, he was appointed First Secretary at the British Embassy in Washington, where he served as the chief liaison between British intelligence and the CIA—giving him unprecedented access to Western operations targeting the Soviet Union.

From this position, Philby systematically betrayed British agents and operations. In 1950, he compromised an Albanian subversion operation designed to overthrow the pro-Soviet government; the British-trained partisans he tipped off were captured or killed. That same year, he identified Konstantin Volkov, a Soviet defector who had offered his services to the British. Philby alerted Moscow to Volkov's defection attempt. Volkov disappeared.