Former chancellor George Osborne will step down as an MP ahead of the general election in June to concentrate on his new career as a newspaper editor.
The Conservative member for Tatton, for six years a key figure in government, wrote to his party's local constituency activists on Wednesday to confirm he was leaving Westminster "for now".
The political and media worlds were shocked in March when it was announced that Osborne would become the editor of the London Evening Standard.
In Wednesday's letter, the contents of which were reported by the Standard, Osborne said: "I am stepping down from the House of Commons – for now. But I will remain active in the debate about our country’s future and on the issues I care about, like the success of the Northern Powerhouse.
"I want a Britain that is free, open, diverse and works with other nations to defend our democratic values in the world.
"I will go on fighting for that Britain I love from the editor’s chair of a great newspaper. It’s still too early to be writing my memoirs.
"I’m very excited about the opportunity to edit the Evening Standard. I’ve met the team there, and their energy and commitment to this great newspaper are positively infectious."
Osborne, who has almost no journalistic experience, was a controversial choice to edit the Standard. The paper's journalists were stunned by the decision – one told BuzzFeed News at the time it was a "kick in the teeth for all hard-working journalists who dream of editing a newspaper one day after years of toil".
While Osborne had claimed that he could combine the role of backbench MP with editing a major newspaper – he pointed out that the Standard goes to press in the morning while parliament sits in the afternoon – opposition politicians said this would be a conflict of interest.
In a statement released after Osborne's appointment, Labour's deputy leader, Tom Watson, said: "I know from conversations with journalists that the long hours and early starts that editing a newspaper like the Evening Standard requires are incompatible with the demands placed on hard-working constituency MPs.
"With that I mind I assume the former Chancellor will give up his seat in Parliament in due course and trigger a by-election, possibly to coincide with the local and mayoral elections being held in May."
Osborn was elected in 2001, replacing Martin Bell, and became the then-youngest MP in the House of Commons.
This is a developing story.