CIA officer who betrayed western intelligence assets and espionage operations to the Soviet Union and Russia

Aldrich Ames, who has died in prison aged 84, was the most senior CIA officer ever to be exposed as a Russian spy. Ames betrayed more than 30 allied agents, at least 10 of whom were executed by the classic KGB punishment of a bullet in the back of the head, and more than 100 clandestine US and British espionage operations.

The US and British agents betrayed by Ames included Maj Gen Dmitri Polyakov, a senior member of the GRU, Soviet military intelligence, who supplied top level information to the CIA, the US foreign intelligence agency, for more than a quarter of a century, and Oleg Gordievsky, an MI6 agent inside the KGB, who, when he was outed by Ames, was the KGB rezident or head of station, in London.