Brexit live: Theresa May faces no confidence vote
A vote of no confidence in Theresa May's leadership is to be held by Conservative MPs.
More than 15% of Conservative MPs submitted a letter calling on her to quit.
A vote will be held by Tory MPs on Wednesday evening to confirm the challenge.
Conservative MPs call on May to quit rather than drag the party through an extended contest.
A no-confidence vote is to be held on Theresa May's leadership after more than 48 Conservative MPs submitted a letter calling for her to stand down.
A statement by the the Chairman of the 1922 Committee of Conservative MPs, Graham Brady, confirmed that 15% of Conservative MPs had called for her to quit, meaning a vote on her future will now go ahead.
He added that a ballot would be held on Wednesday evening by Conservative MPs.
Under party rules more than half of Conservative MPs must support the challenge in order for a full contest to go ahead.
"The threshold of 15% of the parliamentary party seeking a vote of no confidence in the leader of the Conservative Party has been exceeded," Brady wrote.
"In accordance with the rules, a ballot will be held between 1800 and 2000 on Wednesday 12th December."
The prime minister will address the 1922 Committee of Conservative backbenchers this evening before the vote is called.
Under Conservative party rules more than half of May's MPs must support the call for her to stand down in order for a leadership contest to go ahead.
If May were to be successful in such a vote then another ballot on the question of her leadership could not be held for another year, under party rules.
However, if she loses the vote then she will be excluded from any contest. Conservative MPs will then go through a process of selecting their top two candidates for the job of leader, which will then be voted on by all party members.
In a statement, the Chairman and Deputy Chairman of the European Research Group of Conservative MPs, Jacob Rees-Mogg and Steve Baker called on May to quit right away.
"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," they said.
However, May received support from the Home Secretary Sajid Javid, who is seen as one of the favourites to suceeed her.
"The last thing our country needs right now is a Conservative Party leadership election," he tweeted on Wednesday.
"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."
She was also backed by the Work and Pensions Secretary Amber Rudd, who tweeted that "The PM has my full support. At this critical time we need to support and work with the PM to deliver on leaving the EU, & our domestic agenda - ambitious for improvements to people's lives & to build on growth of wages & jobs."