Donald Maclean leaked Washington Embassy secrets before fleeing to Moscow

By Constance Bell · August 20, 2026

British diplomats and their spouses lived double lives for two decades, leaking secrets from the Washington Embassy before vanishing into the Soviet Union.

The trust of the British Foreign Office was traded for Soviet influence long before the Cold War had a name. For twenty years, a "high flying" diplomat sold the inner workings of the Washington Embassy, endangering allies and compromising the West's strategic position.

Richard Curzon and Natasha Frazer

Betrayal on this scale requires a certain kind of invisibility, a skin that can be shed as easily as a name. The file's catalogue entry for KV 2/4140 records that Donald Duart Maclean lived a life of curated identities. While he ascended the ranks of the British civil service, he operated under the aliases Richard Curzon, Mark Frazer, Percy Maclean, and S Madzoevsky.

He was not alone in this choreography of deceit. The catalogue description notes that his wife, Melinda Goodlett Maclean—an American and British national—was equally entwined in the effort. She utilized the aliases Melinda Marling, Melinda Philby, and Natasha Frazer. The partnership suggests a domestic life built entirely upon a foundation of state-level fraud, where the shared secret was not merely a political lean but a professional commitment to a foreign power.

Related catalogue entries, including KV 2/4159, KV 2/4155, KV 2/4152, and KV 2/4153, reiterate these lists of aliases, painting a picture of a couple who existed as ghosts within their own government. For the security services, these were not just names; they were the gaps in the fence through which the most sensitive diplomatic communications of the era flowed.

A High Flying Employee

There is a particular bitterness in the phrase "high flying employee," a term used in the catalogue entry to describe Maclean's status within the Foreign Office. It describes a man who was not merely tolerated by the establishment but embraced by it. According to the public record, Maclean's career was a trajectory of prestige: Third Secretary in Paris in 1938, postings in London and Washington, D.C., and eventually the role of head of the American Department in the Foreign Office.

This ascent occurred while Maclean was, as the catalogue entry records, "assessed as having been a Soviet agent since the 1930s." The timeline is a damning indictment of the vetting processes of the time. While Maclean was being promoted to First Secretary and entrusted with the delicate machinery of Anglo-American relations, he had already been compromised for years. The very qualities that made him "high flying"—his intellect, his connections, and his seamless fit within the diplomatic elite—were the tools he used to mask his service to Moscow.

He was the perfect insider because he looked, spoke, and thought like the men he was betraying. The cost of this blind spot was a steady hemorrhage of intelligence from the heart of the British state, delivered by a man who had spent a decade proving his loyalty to everything except his own crown.

May 1951

The masquerade finally collapsed in 1951. The file's catalogue entry records that Maclean was identified as the source of a "leakage from the Washington Embassy some years earlier." The exact nature of that leakage—the specific cables, the names of assets, or the strategic plans exposed—is not detailed in the catalogue summary, but the consequence was immediate. Maclean became the subject of a Security Service investigation.

Rather than face the consequences of his treason, Maclean chose a final, dramatic alias: a fugitive. The catalogue description for KV 2/4140 notes that while under investigation, he fled to the USSR. He did not go alone.

According to the catalogue entry for KV 2/4107, Guy Francis De Moncy Burgess—who operated under the aliases Roger Styles and Jim Andreyevich Eliot—disappeared from London in May 1951 along with Maclean. Both men had been assessed as Soviet agents since the 1930s. The record for Burgess ends abruptly, with a truncated note stating, "This file contains papers dealing with BURGE," leaving the final accounting of his activities in the gap of a clipped sentence.

They reappeared in Moscow, leaving the British government to survey the wreckage of a twenty-year breach. The catalogue entry for KV 2/4107 records that Burgess and Maclean had operated in the shadows of the British state since the 1930s, an unresolved window of vulnerability that suggests the leak in Washington was only one symptom of a much deeper infection.