Later this evening Theresa May will face a leadership challenge from Tory MPs after delaying a Commons vote on her Brexit deal.
Why is the vote taking place?
Sir Graham Brady, chairman of the Conservative backbench 1922 Committee, has confirmed the threshold of 48 letters of no confidence had been exceeded meaning the Prime Minister has lost the support of 15% of her MP’s.
The PM has been relentless in seeking to deliver Brexit, with Parliamentary numbers stacked to try to frustrate, delay & block.
She has remained focused, determined & courteous throughout.
I will be 100% backing the PM 🗳
— Justin Tomlinson MP (@JustinTomlinson) 12 December 2018
What happens in the no confidence vote?
Theresa May will need the support of 158 of the 315 Conservative MPs to stay in office.
Even if she wins, if the margin of victory is small her authority may have been fatally wounded.
When will the vote be held?
The ballot is held between 6-8pm this evening, and the result is expected to be announced shortly afterwards.
What if Theresa May loses?
If the Prime Minister were to lose the vote there would be a leadership contest arranged, May would not be able to stand in the subsequent contest arranged by Sir Graham.
How would the leadership contest work?
Candidates for the leadership must be nominated by two Conservative MPs.
If only one candidate comes forward, he or she becomes leader.
If a number of would-be leaders are nominated, the list is whittled down to a shortlist of two in a series of votes by MPs.
The final pair then go to a postal ballot of all party members, with the position of leader, and Prime Minister going to the victor.
How long would that take?
Sir Graham would be responsible for overseeing the contest and setting a timetable for the campaign, which would be expected to last around 12 weeks.
Who are the contenders to take over as Tory leader?
Bookmakers have Boris Johnson and Dominic Raab as joint favourites, followed by Michael Gove and Sajid Javed.