He served 10 years in prison when his role as a Soviet spy was exposed. He spent eight years passing secrets to the Russians before one of the most bizarre treachery scandals of the century shook British counter-intelligence to its foundations.
Vassall, who took the name John Phillips when he was released from prison, was a weak-willed gullible homosexual sent to Moscow at the height of the Cold War as a junior naval attache at the British embassy.
It was a decision which later baffled government, because he was so clearly vulnerable to Kremlin blackmail. He was enticed by Russian secret service agents to a party where heavy drinking led to male guests stripping and being photographed in lewd poses.
Risking exposure as a pro- miscuous homosexual if he failed to cooperate, Vassall began passing secrets in 1954 and continued as a spy when he returned to London in 1956 to work in naval intelligence.
While the British failed for some time to isolate Vassall as the traitor in their midst, they eventually realised that this humble assistant private secretary on a salary of pounds 15 a week was keeping an expensive flat in Westminster and holidaying in New York, Capri and Rome.
At his trial, he was accused of "selling his country for lust and greed" and the subsequent inquiry showed up British intelligence in a most unflattering light.
He was jailed for 18 years in 1962 after admitting four offences under the Official Secrets Act. He was released in 1972 and attempted to rebuild his life working for the British Records Association, archivists near his home in St John's Wood, north-west London.Reuse content