David Cameron’s favourite after dinner anecdote, that he was approached by the KGB on a trip to Russia when he was just 18, was in fact just a “gay pick-up” by a couple of black-market salesmen, a Russian expert has claimed.

Recalling his gap-year, spent finding himself with a friend in the former USSUR, Cameron claims that “two Russians who spoke perfect English sort of turned up on the beach, which was mainly reserved for foreign tourists.”

“They took us out to dinner and interrogated us in a friendly way about life in England and what we thought and politics,” says Cameron, who on return to the UK had his suspicions confirmed by a tutor; it was an attempt to sign the future PM up to the KGB, the USSR's notorious secret service.

But Russian security analyst, Gennady Sokolo, is not convinced by Cameron’s story.

"If the KGB had a task to work with a 19-year-old unknown young man Cameron, there would have remained certain paperwork on this matter,” claimed Sokolo, in an interview with the Komsomolskaya Pravda newspaper.

"We have cautiously asked well-informed people if there is a file on Cameron in KGB archives. We got a definite reply that there is no such file in the archives, and there was no such file earlier. The KGB was not working on Cameron."

Sokolo has even claimed that he’s tracked down the two men, who he says were in fact just black market salesmen attempting to buy banned Western goods from tourists.

He said: "The pair planned to buy some foreign stuff like jeans to resell them later and, after all, to make friends with two nice looking British guys - there was also a gay motive."