Conservative Richard Spring became the latest MP to join the growing exodus from the Commons today when he announced he would step down at the next general election.
Spring, a former Tory vice-chair and ministerial aide, said he was quitting "with very mixed feelings" after representing first Bury St Edmunds and then West Suffolk from 1992.
More than 100 MPs are not defending their seats at the next election – some of them in direct response to controversy over their expense claims or the wider Westminster pay and perks scandal.
Spring escaped unscathed from the revelations about claims earlier this year.
In a letter to his constituency party chairman announcing his intention, he said it had been the "greatest possible honour" to represent the area.
"I have taken the decision with very mixed feelings," he went on, pledging his support for whoever is chosen to succeed him as the Tory candidate.
Spring, who also held a string of shadow ministerial positions until 2005, won with a majority of 8,909 in 2005, meaning another selection contest for a safe seat.
It could provide a fresh test of party leader David Cameron's attempt to secure berths for preferred candidates in a bid to boost the number of female and ethnic minority Tory MPs.
The election must be held by 3 June.