Former Liberal Democrat frontbencher Mark Oaten has announced he will step down as an MP at the next election, six months after being engulfed in a sex scandal.
The married MP for Winchester resigned from his job as the party's home affairs spokesman in January after it emerged he had had an affair with a male prostitute.
In a statement, the 42-year-old said: "At the next general election, my Winchester constituency will be replaced by two new seats and I have confirmed to the local party that I do not intend to contest either of the new constituencies.
"I hope that prospective parliamentary candidates can be found at the earliest opportunity and I would like to offer them and the party my full support."
News of the affair came just days after Mr Oaten pulled out of the race to succeed Charles Kennedy as Lib Dem leader, although he insisted this withdrawal was due to a lack of support in the parliamentary party.
When the story broke, the MP apologised for "errors of judgment in personal behaviour", but a month later he told his local newspaper he wanted to continue to represent Winchester in parliament.
However, in his statement last night, the father-of-two said: "I will continue to work for all my constituents both locally and at Westminster, where I also hope to focus on human rights and third world development issues.
"At the time of the next election I will have served over 12 years as an MP and, having spoken with my wife Belinda, we feel it will be the right time for us to take on new challenges."
In an interview with the Sunday Times in May, Mr Oaten revealed that a mid-life crisis was partly to blame for his six-month affair with a 23-year-old male prostitute, citing an early onset of balding in particular.
On learning about the affair, he said his wife had thrown her wedding ring at him.
Part of the existing parliamentary seat of Winchester will be moved to a new constituency, Meon Valley, at the next general election following a recommendation by the Boundary Commission.
Mr Oaten currently has a majority of 9,643 in Winchester, but an analysis of the new constituency suggests it may be a Lib Dem - Conservative split.