Kirsty Young's castaway this week is Oleg Gordievsky. He is the highest-ranking KGB officer ever to become a spy for the British. The insights he gave into the Soviet hierarchy and culture over the course of 10 years were so significant that, according to some, he did more than any other individual in the West to hasten the demise of the communist regime. A bright pupil with an aptitude for languages, he joined the KGB's diplomatic corps thinking it would allow him to travel and fulfil his interest in politics. But he was first enchanted by the liberty enjoyed in the West and then so horrified by the Soviet invasion of Czechoslovakia that he started to feed information to MI6.

He risked his life for a decade, but in 1985 he was recalled to Moscow - his cover had been blown and he realised he had just weeks to live. An incredible escape plan was activated and, after shaking off the KGB surveillance teams that followed him everywhere, he escaped by tram, train and bus to the border with Finland - where British agents bundled him into the boot of a car and carried him to freedom.

Now, his life is in Britain - he has married a British woman and his courage has been recognised through the honours system. But he believes his existence is a precarious one - after the death of his friend Alexander Litvinenko last year he has felt increasingly worried about his own safety and believes Britain is no longer the safe haven it once was.

[Taken from the original programme material for this archive edition of Desert Island Discs]

Favourite track: Erbarme Dich by Johann Sebastian Bach