No-confidence vote: How Theresa May could be ousted by Conservative MPs tonight

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The vote of no confidence is underway and by 9pm tonight we should know if we will have a new prime minister.

Here is everything you need to know before then...

1. How did we get to this point?

   Under Tory rules once 48 letters calling for the prime minister to resign have been handed to Sir Graham, then the vote of no confidence must be held.

   The system was created after Iain Duncan-Smith was deposed as leader and have not been tested since, making this the first no-confidence vote of its kind in the party’s history.

   Regulations under this system mean that the names of those handing the letters in are confidential, so no MP knows if his or her letter will be the one to tip the balance.

   Sir Graham, who has presided over the rules since becoming chair of the 1922 in 2010, explained how they are set up to make MPs think carefully before submitting their letter.

   While there have been several times when rebels claimed to be close to the 48 threshold, only Sir Graham truly knows the numbers and who submitted letters. He admitted that there had been a particular amount of “action” on Tuesday, leading to him calling the PM last night.

   He said the prime minister had expressed a view that the vote be held quickly.

2. What are the timings?

   The prime minister will go to a room along the corridors of the Palace of Westminster at 5pm to address her backbench MPs, and will take questions from them, in what could be a critical hour for her leadership.

   At 6pm after she has made her final pleas, the ballot will open for two hours. MPs will be given a piece of paper and will mark an “X” next to either the sentence, “I have confidence in Theresa May to lead the Conservative Party”, or “I do not have confidence in Theresa May to lead the Conservative Party”.

   The vote will be administered by the officers of the 1922. Once it is closed, the metal ballot box will be taken to an adjacent room, and the votes counted by just three people – Sir Graham Brady, Cheryl Gillan and Charles Walker.

   MPs and others will then be let into the room for the announcement, which will also be broadcast live from parliament, at or soon after 9pm if all goes to plan.

3. How many MPs will vote?

   There are 315 MPs sitting for the Conservative Party, with all allowed to vote. The prime minister, Sir Graham Brady and all ministers are allowed to cast a ballot.

   To win Ms May must get the backing of 50 per cent of the vote plus one. That will probably mean 158 votes at least, but if she can only narrowly win she may feel pressure to resign.

   The exact numbers of who will vote in the contest were still unclear this morning, because there are two MPs who have had the Tory whip removed, Charlie Elphicke and Andrew Griffiths.

   It is possible that the government chief whip could reinstate the whip to these two MPs before the vote takes place, changing the dynamic of the result if it is very close.

   The Speaker of the House John Bercow, who was elected as a Conservative MP, will not get to vote in the contest because he does not accept the party whip due to his parliamentary role.

4. If she loses, how will the leadership contest work?

   Once Ms May has gone, contenders will put their names forward to replace her. There will be several rounds of voting among all MPs to whittle them down to just two to put to a vote of the membership.

   Sir Graham has said that the parliamentary rounds could start on Monday if they need to and be completed by the Christmas break, with the postal ballot of members done in the new year.

   The aim would be to get it done and have a new leader before January 21 when the commons is supposed to vote on the Brexit deal agreed with the EU.