The KGB claimed it was behind 1980s protest marches, where Jeremy Corbyn was often a speaker

In the 1970s and 1980s the KGB and its Soviet allies launched an intensified campaign to recruit figures on the British left that was systematic, well-funded and, in terms of espionage, remarkably ineffective.

Communist spooks from the Soviet Union, Czechoslovakia, Poland and even Cuba went to great efforts to establish contact with sympathetic politicians, journalists and opinion formers. They lunched, flattered and frequently paid their contacts and fellow travellers in “red gold”.

A Czech spy claimed to have met Mr Corbyn “more than ten times” PETER BROOKER/REX

Two of the most important defectors to Britain revealed, however, that the results were strictly limited: a long list of contacts, a fortune in expenses claims, but no one who could really be described as a spy.

The efforts of the KGB and the StB, its Czech counterpart, were aimed at exerting political