Donald Maclean Sold Washington Embassy Secrets Before Fleeing to Moscow

By Constance Bell · August 19, 2026

He operated as a Soviet agent since the 1930s, utilizing a network of aliases to compromise the Foreign Office before escaping to the USSR in 1951

Every cable sent from the British Embassy in Washington during the early 1940s was effectively a postcard to the Kremlin. The trust between the United Kingdom and the United States was compromised by a man who occupied the very center of their diplomatic intimacy, turning the Foreign Office into a conveyor belt for Soviet intelligence.

The depth of this penetration is laid bare in the archives of the UK National Archives. The file's catalogue entry for record KV 2/4145 describes the trajectory of Donald Duart Maclean, a man the security services termed a "high flying employee of the Foreign Office" who spent decades selling out his own government.

"A High Flying Employee"

Elite status in the British civil service is often mistaken for loyalty. For Maclean, it was merely a more efficient way to access secrets. According to the public record, Maclean’s ascent was rapid: a Third Secretary in Paris by 1938, followed by postings in London, Washington, and Egypt, eventually rising to head the American Department in the Foreign Office. He was the ideal operative—trusted, invisible, and perfectly positioned to monitor the Anglo-American alliance during the Second World War.

The catalogue entry for KV 2/4145 notes that by 1951, the British security apparatus finally identified Maclean as the source of "a leakage from the Washington Embassy some years earlier." The word "leakage" is a sanitized term for a systemic hemorrhage of intelligence. By the time the Security Service caught up with him, the damage had been done across two decades. The record assesses that Maclean had been a Soviet agent since the 1930s, meaning his entire professional life was a choreographed performance funded and directed by Moscow.

Richard Curzon and the Art of the Alias

Espionage at this level requires a fragmented identity. The catalogue descriptions for KV 2/4145 and its related files—including KV 2/4140, KV 2/4159, KV 2/4155, KV 2/4164, and KV 2/4141—detail a dizzying array of aliases used by Maclean to mask his movements and communications. He operated under the names Richard Curzon, Mark Frazer, Percy Maclean, and S Madzoevsky.

This pattern of deception extended to his domestic life. The archival entry lists his wife, Melinda Goodlett Maclean, as also possessing a suite of aliases: Melinda Marling, Melinda Philby, and Natasha Frazer. The existence of these names suggests a partnership in secrecy, an American-born woman entwined in the web of a British traitor. The use of such diverse identities indicates that the Security Service was not merely tracking a single rogue diplomat, but a sophisticated cellular operation that treated the diplomatic corps as a playground for deception.

The Flight to the USSR

When the walls finally closed in, the establishment's shock was matched only by the speed of the escape. The catalogue entry records that "while under investigation he fled to the USSR with Guy Burgess." The disappearance of two high-ranking officials was a humiliation for the British intelligence community, proving that the rot in the Foreign Office was not an isolated incident but a systemic failure.

It is telling that the files on Maclean are housed within the "Personal (PF Series) Files" under the specific heading "SOVIET INTELLIGENCE AGENTS AND SUSPECTED AGENTS." This categorization strips away the prestige of his "high flying" career, reducing the diplomat to a line item in a list of enemies of the state. The repetition of Maclean's details across six different catalogue references suggests an investigation that was fragmented and sprawling, reflecting a government struggling to grasp the scale of the penetration.

While the public record remembers the Cambridge Five as a collection of intellectual rebels, the archival descriptions paint a colder picture of professional betrayal. Maclean did not just share ideas; he provided the Soviet Union with a map of British diplomatic intentions during the most volatile years of the twentieth century.

Beyond these catalogue entries, other records of the era remain, including the UK National Archives' CSC 11/171 and KV 2/4160, though their specific contents are not detailed here. What remains certain is that for twenty years, the man responsible for the American Department of the Foreign Office was reporting to the very power he was tasked with containing. The record ends with his flight to the USSR, leaving the full extent of the "leakage" from Washington to be guessed at by those left behind.