Theresa May could be removed as prime minister tonight after a vote of no-confidence in her leadership was triggered by furious Tory MPs.
Sir Graham Brady, chairman of the 1922 Committee of Conservative backbenchers, announced this morning that the 48-letter threshold to trigger a ballot had been reached and that the vote will begin at 6pm.
He said: "The threshold of 15% of the parliamentary party seeking a vote of confidence in the leader of the Conservative party has been exceeded.
"In accordance with the rules, a ballot will be held between 18.00 and 20.00 on Wednesday 12 December in committee room 14 of the House of Commons. The votes will be counted immediately afterwards and an announcement will be made as soon as possible in the evening."
May will fight for her political life as she delivers a speech to warring Tory MPs ahead of the vote.
Cabinet ministers immediately offered their support to the prime minister, and criticised those trying to remove her from office.
Justice secretary David Gauke told LBC radio: "The idea that we should remove the prime minister at this stage is frankly irresponsible and self-indulgent."
Home secretary Sajid Javid - tipped as a possible replacement - said on Twitter: "The last thing our country needs right now is a Conservative party leadership election. Will be seen as self-indulgent and wrong. PM has my full support and is best person to ensure we leave EU on 29 March."
Communities secretary James Brokenshire, a close ally of the prime minister, tweeted: "Strongly support @theresa_may to continue as Leader of @Conservatives and Prime Minister.
"Now is not the time for this distraction and even more uncertainty. We need to get behind the Prime Minister in the best interests of our country."
James Cleverly, another potential leadership candidate and Tory deputy chairman, said: "Clearly I’m disappointed that some in my party have triggered a vote of no confidence just as the PM is having a series of international meetings to deliver Brexit. I will, of course, be voting in support of Theresa May."
But in a joint statement, Jacob Rees-Mogg and Steve Baker of the Brexiteer European Research Group said: "‘Theresa May’s plan would bring down the government if carried forward. But our party will rightly not tolerate it.
"Conservatives must now answer whether they wish to draw ever closer to an election under Mrs May’s leadership. In the national interest, she must go."
Pressure has been mounting on the prime minister since her decision to delay the vote on her Brexit deal, which had been due to take place last night.
One senior Conservative MP told CSW's sister site PoliticsHome he had spoken to a handful of colleagues who had submitted letters of no confidence since May was forced to delay the meaningful vote on her Brexit deal on Monday.
"She was acting in her own self-interest, not in the national interest," said the MP, who predicted that she would be "gone by Monday".
May, who travelled to Europe yesterday to plead with EU leaders to offer her some concessions on the Northern Ireland backstop, will chair what could turn out to be her last Cabinet meeting as prime minister in Downing Street this afternoon.