Mark Oaten, the Liberal Democrat MP who was exposed for using male prostitutes, has claimed he had a sexual relationship with an older man at the age of nine or ten.

The married MP, 45, who was forced to quit his bid for the party leadership, is publishing a tell-all memoir next month titled Screwing Up.

He says the relationship was with a much older man who was in a “position of trust”.

“Clearly it was wrong, but it happened and I’ve not even been that worried about it,” he said. “I have never felt abused, hold no grudge and do not wish to drag the case up today.”

Oaten said he recalled the relationship during counselling sessions following the sex scandal which broke in January 2006.

After details of his dalliances with rent boys became public, he said male pattern baldness and a mid-life crisis had contributed to his extra-marital activities.

He plans to stand down his seat as MP for Winchester at the next election.

According to publisher Biteback, the book is a tale of “a man obsessed by retaining his youth, fearful of turning 40 and feeling a complete failure”.

It is due for release on September 18th – the day before the Liberal Democrat Party Conference.

In an interview with Press Gazette in April, Oaten said that the News of the World, which broke the story of his use of male prostitutes, had known of his activities for around three years but had chosen to wait until he was more famous to report on them.