Stephen Hammond has become the latest MP to confirm they will call it quits at the next election.
The Wimbledon MP and former minister will join a Conservative exodus, with more than 40 announcing that they will not defend their seat in an election that is likely to take place next year.
In a letter to his local party association on Thursday, Mr Hammond said he would “not seek the nomination” as the Tory candidate following what he called an “incredibly tough decision”.
He said: “It has not been easy for me to make this decision and, despite the national picture, I do believe we can win locally.
“However, this is the right decision for Sally (his wife) and me.
“In recent years we have both been stretched by increased caring responsibilities for our elderly parents and this is unlikely to change in the coming years.”
He said it had been the “privilege of my life” to represent Wimbledon in Westminster for the past 18 years.
The 61-year-old was first elected to Parliament in 2005 and was promoted to the government front benches in 2012, being handed a junior transport role by David Cameron during the coalition years before losing his position in a reshuffle two years later.
During the Brexit years, he was twice punished for rebelling against Tory governments.
Former prime minister Theresa May sacked him as vice-chairman of the party in 2017 after he voted in favour of a so-called “meaningful vote” on her Withdrawal Agreement.
In September 2019, he was one of 21 MPs stripped of the Tory Party whip by then-prime minister Boris Johnson after they backed a plan to take control of the Commons timetable to pass legislation to block a no-deal Brexit.
He and nine others later had the whip restored following talks with Mr Johnson a month later.
Mr Hammond made an appearance at Prime Minister’s Questions on Wednesday, asking Rishi Sunak whether he would consider convening a dementia medicines taskforce to review progress on a new diagnostic test and drug treatment.
With Mr Sunak’s Tories well behind in the polls, a host of senior party MPs have chosen not to fight for another term.
Former defence secretary Ben Wallace and former cabinet ministers Dominic Raab, George Eustice, Matt Hancock and Sajid Javid have all called time on their Commons careers.