Donald Maclean Used Four Aliases to Defraud the Foreign Office

By Harlan Pryce · August 20, 2026

A high-flying diplomat's double life stayed hidden for two decades until he fled to the USSR in 1951, leaving behind a trail of leaks from the Washington Embassy.

A high-flying diplomat spent twenty years selling out his colleagues and his country from the heart of the Foreign Office. The cost was a compromised embassy in Washington and a security apparatus left staring at a vacancy where a trusted official had once stood.

There is a specific kind of arrogance required to climb the ranks of the civil service while operating as a foreign asset. It requires not just a mastery of tradecraft, but a profound contempt for the institutions one pretends to serve. Donald Duart Maclean was the archetype of this breed: the man who fit in so perfectly that his presence was seen as an asset rather than a vulnerability.

Richard Curzon and Four Others

The scale of the deception is best measured by the number of identities Maclean maintained to shield his activities. According to the file's catalogue entry for KV 2/4156, Maclean operated under several aliases, including Richard Curzon, Mark Frazer, Percy Maclean, and S Madzoevsky. These were not merely casual pseudonyms; they were the tools of a man who lived a fragmented existence, moving between the corridors of power and the shadows of Soviet intelligence.

He did not act alone. The record shows that his wife, Melinda Goodlett Maclean, was equally embedded in this network of falsehoods. The catalogue entry for KV 2/4156 records that she used aliases such as Melinda Marling, Melinda Philby, and Natasha Frazer. In the world of clandestine service, a spouse who shares the burden of aliases is not just a partner, but a co-conspirator. The transition from a high-society American and British couple to a pair of Soviet assets required a level of coordination that suggests their marriage was as much a tactical arrangement as a romantic one.

May 1951

The mask finally slipped in 1951. The file's catalogue entry records that Maclean was identified as the source of a leakage from the Washington Embassy that had occurred some years earlier. Once the Security Service began to close in, the "high flying" diplomat did not wait for a tribunal or a trial. Instead, he chose the exit strategy common to the ideological turncoats of his generation.

While under investigation, Maclean vanished. He did not go alone. Related catalogue entries KV 2/4107 and KV 2/4119 describe the disappearance of Guy Francis De Moncy Burgess from London in May 1951. Burgess, who also operated under aliases such as Roger Styles and Jim Andreyevich Eliot, fled alongside Maclean. The two men, bound by a shared commitment to a foreign power, reappeared in Moscow.

For the Foreign Office, the flight of Maclean and Burgess was more than a security breach; it was a public humiliation. It proved that the very mechanisms used to vet and promote the elite of the British diplomatic corps had been turned against them. The men the establishment trusted to protect the realm were the ones handing the keys to the enemy.

A Soviet Agent Since the 1930s

The most damning detail in the record is the timeline of the betrayal. The Security Service did not discover a sudden lapse in judgment or a temporary flirtation with Moscow. As noted in the catalogue descriptions for KV 2/4156, KV 2/4153, and KV 2/4147, Maclean was assessed as having been a Soviet agent since the 1930s.

This means that for the entirety of his ascent through the civil service—from his early appointments to his role as a First Secretary in Washington—Maclean was an agent of the USSR. Every report he wrote, every cable he read, and every confidence shared with him by a fellow diplomat was potentially a delivery for Moscow. He spent two decades occupying a position of trust while ensuring that trust was weaponized against the British state.

When one looks at the names listed in the PF Series files—the "Soviet Intelligence Agents and Suspected Agents"—it becomes clear that the threat was not an external force breaking in, but an internal rot. Maclean and Burgess were not intruders; they were the architects of their own promotions, using their access to make themselves indispensable while they hollowed out the embassy's secrets.

The catalogue entries for KV 2/4156, KV 2/4153, and KV 2/4147 all conclude with the same assessment: Maclean had been a Soviet agent since the 1930s.