Leading Brexiteer Jacob Rees-Mogg has submitted a letter of no confidence in Theresa May, increasing the threat of a Tory leadership challenge.
The Tory MP said it was “in the interest of the party and the country if she were to stand aside”, but later insisted he was not staging a “coup” against the prime minister.
Several other Conservative MPs – including Henry Smith, Simon Clarke, Laurence Robertson and Anne Marie Morris – also confirmed on Thursday they had submitted their own letters amid growing discontent over the PM’s Brexit plan.
Mrs May has previously insisted she will lead the Conservatives into the next general election and her spokesman insists she will fight any vote of confidence against her.
But as Tory MPs continue to ramp up the pressure on Mrs May amid a string of government resignations, how likely is the threat of a leadership election and what do they need to do to force a challenge?
:: The magic numbers – 1922 and 48
Mrs May’s fate hangs in the balance of the 1922 committee – the parliamentary group of Conservative MPs.
To trigger a vote of no confidence, its chair has to receive letters from 15% of them – 48 at present – formally calling on the leader to stand down.
The process is completely blind, so only the current chairman Sir Graham Brady knows how many letters have been submitted and by whom.
Several MPs publicly announced they had put in letters as part of a bid to unseat Mrs May in July, following the resignations of Boris Johnson and former Brexit secretary David Davis.
They remain on file, unless withdrawn.
When 48 letters are submitted, it triggers a confidence vote.
The prime minister needs a simple majority – half their MPs’ votes plus one – to win. If they do, they get immunity from another formal challenge for a year.
:: What happens if they lose the confidence vote?
A date for the first round of the leadership election would be chosen by Mr Brady, in consultation with the prime minister.
Contenders to replace them will be nominated, but must get the backing of 15% of Tory MPs.
Depending on how many candidates there are, rounds of elections will be held, with the MPs with the fewest votes dropping out of the race one by one.
That all changes when there are two candidates left – Conservative Party members will have the final say in an open election.
Mrs May managed to win without going through this final phase, because her opponent, now-Commons leader Andrea Leadsom, dropped out for suggesting being a mother made her better qualified.
If there is a contest, the winner will be announced by Mr Brady.
If parliament wants to get rid of the prime minister, it has to table a vote of no confidence.
All 650 MPs would get the chance to vote formally on whether Mrs May should stay as leader or resign, with the expectation that a general election would follow.