Tom Watson, the deputy leader of the Labour Party, has announced he will not stand in the general election.
In a letter to Jeremy Corbyn published on Wednesday evening, Watson said he wanted to “start a different kind of life”.
“The decision is personal, not political,” he said.
“This election is a turning point for our country and I know that Labour goes into it united in our determination to remove the Conservative government that has done so much damage to the communities Labour was founded to represent.”
Watson, who has been the MP for West Bromwich East since 2001, added while he was quitting as an MP he would not be “leaving politics altogether”.
He was elected Labour’s deputy leader in 2015 and intends to stay in post until polling day on December 12.
Watson has had a more than fractious relationship with Corbyn. In September he narrowly saw off an attempt by allies of the Labour leader to oust him from his deputy post.
Corbyn said he “sincerely” thanked Watson for “on behalf of everyone in our movement for your contribution to this party over the last 30 years”.
The Labour leader added: “I’ve always enjoyed our very convivial chats about many things, including cycling, exercise and horticulture. I hope the horseradish plants I gave you thrive.”
Sadiq Khan, the Labour London mayor, meanwhile, said Watson’s “energy, passion for politics and commitment to campaigning” would be missed.
Owen Smith, the former shadow Northern Ireland secretary, who challenged Corbyn for the leadership in 2016, tweeted: “All the very best for the future, Tom. You’ve been a true leader for Labour.”
Former Ashfield MP Gloria de Piero said: “Thank you Tom for a lifetime of dedication to the Labour Party and just as importantly thank you for 25 years of friendship.”
There was speculation that Watson’s resignation would be followed by other party moderates who had been critical of Corbyn’s leadership, but Labour candidates, including Darren Jones and ex-leadership candidate Liz Kendall, were quick to deny such claims.
Watson’s supporters will celebrate his campaign achievements, such as tackling problem gambling and challenging phone hacking.
Daniel Janner, the son of the late Labour MP Lord Janner who was one of the victims of the VIP abuse probe sparked by Carl Beech, however, said Watson’s position had become “untenable”.
Janner has been a fierce critic of Watson, who he has previously been accused of applying “pressure on the police” over the investigation.
Watson is the latest of several high profile MPs to announce they are stepping down.
More than 60 MPs, including culture secretary Nicky Morgan and former chancellor Philip Hammond, are leaving Westminster.
Make sense of politics. Sign up to the Waugh Zone and get the political day in a nutshell.