Mr Cameron said he enjoyed his jousts with Tony Blair

Cameron interview

In an interview for BBC Radio 4's Desert Island Discs he told how suspect agents "interrogated" him in Yalta in what may have been a recruitment drive.

The MP also talked about his disabled son, who suffers from a combination of epilepsy and cerebral palsy.

He picked an eclectic mix of music for his desert island, ranging from Benny Hill to The Killers and Mendelssohn.

The Witney MP told Sue Lawley he would take a crate of whisky as his luxury and TV chef Hugh Fearnley-Whittingstall's River Cottage Cookbook as his book.

CAMERON'S DISCS Ernie (The Fastest Milkman in the West) - Benny Hill Tangled Up In Blue - Bob Dylan This Charming Man - The Smiths On Wings of Song - Mendelssohn Wish You Were Here - Pink Floyd Fake Plastic Trees - Radiohead Perfect Circle - REM All These Things I've Done - The Killers

The story behind Cameron's favourite song

The suspected KGB approach from Russian intelligence came while he was travelling in his year out between school and university.

He met a friend in Moscow and went to Yalta on the Black Sea coast, where two Russians speaking "perfect English" had turned up on a beach mostly used by foreigners.

"They took us out to dinner and interrogated us in a friendly way about life in England and what we thought and politics," he said.

"We were obviously very careful and guarded in what we said but later when I got to university my politics tutor said that was definitely an attempt."

Wonderful boy

Mr Cameron said the incident had raised eyebrows when he was being vetted to become a special adviser at the Treasury in the 1990s.

His story had made the vetting officer fill his notebook, he said.

Hill spent four weeks at number one

Mr Cameron also talked openly and honestly about the shock of learning of his son Ivan's disability.

Born in 2001, Ivan is the eldest child of Mr Cameron and his wife Sam and has a rare condition combining epilepsy and cerebral palsy that has left him needing 24-hour care.

Mr Cameron told interviewer Sue Lawley the condition was apparent within a few days of Ivan's birth.

He said: "You obviously worry about everything as a parent and you start asking questions.

"Initially, we were told it was fine, then we went to hospital and they ran some tests and we were told he had a very rare condition which has very poor outcomes.

He said the news hit "almost like mourning the loss of something, because you are mourning the gap between your expectation and what has happened," he said.

He is a wonderful boy. He has got the most lovely eyes and he definitely interacts with us in the way he looks at you and the way he moves his head,

David Cameron, Conservative leader

"The thing that worries us is his quality of life and trying to make sure he does have a good quality of life."

But he added: "He is a wonderful boy. He has got the most lovely eyes and he definitely interacts with us in the way he looks at you and the way he moves his head, but he often is in a lot of pain."

He and his wife are "positive, optimistic people" he said and are determined to give Ivan all they can and ensure he is part of the family. The couple have two other children, Nancy, now two and Arthur born earlier this year, both of whom were born without Ivan's medical problems.

In the interview Mr Cameron also suggested he quite enjoyed his jousts with Tony Blair in the House of Commons.

He said: "Prime minister's questions with Tony Blair there is some sort of light and shadow and he's got a sense of humour...

"I'm not sure with Gordon [Brown] how many light moments there will be."

Childhood memories

Mr Cameron insisted he had not given up on his promise to end "Punch and Judy" politics.

But he admitted the Commons was a theatre, adding "You have to do a bit of bopping from time to time."

The Tory leader said the live version of Bob Dylan's Tangled Up In Blue would be the song he would take to his desert island if only allowed one record.

The sound of the audience and Dylan's "rasping voice" would make him feel less lonely, he said.

Mr Cameron revealed his childhood musical hero is none other than saucy old-school comic Benny Hill.

He said the comedian's 1971 chart-topper Ernie (The Fastest Milkman in the West) was the only song he knows all the words to.

"This really just reminds me of my childhood," he said.

Desert Island Discs is broadcast at 1115 BST on Sunday.