No confidence vote: who will be the next prime minister?

'The agenda I set out in my first speech outside this front door - delivering the Brexit people voted for, building a country that works for everyone - I have dedicated myself unsparingly to these tasks ever since I became prime minister and I stand ready to finish the job' - UK Prime Minister Theresa May outside 10 Downing Street.

May will have to make the speech of her career ahead of a crucial vote of no confidence in her leadership amid the chaos of Brexit. The furore over the Irish backstop and her decision to pull the meaningful vote on her Brexit deal has caused the divisions in her party to boil over and now her colleagues will decide her future.

Read more: Theresa May pulls Brexit vote in parliament amid fears of defeat

May has vowed to 'contest the vote with everything I’ve got' and has argued a leadership contest would have grave consequences. May claims a leadership contest would mean a new prime minister couldn’t be voted in and strike a new deal with the EU before the legal deadline for a vote on the Brexit deal on 21 January 2019, and even Brexit on 29 March. This means, May says, that ousting her would require Article 50 to be extended 'or even revoked' and risks handing power to opposition MPs in parliament.

Conservatives submit 48 letters of no confidence

The vote on May’s future has been called after at least 48 Conservative MPs (15% of the parliamentary party) submitted letters of no confidence in her leadership to the chair of the 1922 Committee, Graham Brady.

A campaign led by the European Research Group – a Conservative research firm led by rebel backbencher Jacob Rees-Mogg - to unseat May has been gaining traction for weeks but had previously failed to secure the minimum number of letters needed for the vote to be called.

Over 20 MPs have publicly announced they are part of the revolt against May, including former Brexit minister Steve Baker.

The Labour party had pledged to put forward a vote of no confidence if May’s deal was voted down but failed to follow through after she postponed the meaningful vote. Some argue this is because Labour is still struggling to come up with any viable alternative to what’s already on offer while others believe the opposition have been able to sit back and watch the government tear itself apart.

No confidence vote: when is it and how does it work?

The vote on May’s leadership will be held on 12 December between 6pm and 8pm. The prime minister will need to secure a majority to keep her job. That requires her to rally support from at least 158 Conservative MPs, but many believe she needs a bigger backing to truly stave off the challenge and remain at the helm. It will be a secret ballot. There is widespread expectation that May would still resign if she can only get a slim majority.

What happens if May wins the vote of no confidence?

Those looking to oust May only get one shot. If enough MPs are willing to back her and convince May that she has a mandate within her own party to continue then she will remain as prime minister and won’t be able to be challenged again for at least 12 months.

The lack of support for her Brexit deal is what has got May into this mess in the first place but if she manages to survive the vote with a significant majority then it could end up working in her favour. Winning would mean discussions about leadership would dissipate and allow her to show the European Union that while there is no agreement on the Brexit deal there is support for her leadership. The EU, aware that May wouldn’t be going anywhere, may be more inclined to renegotiate to avoid a Hard Brexit.

What happens if May loses the vote of no confidence?

If May loses the vote or resigns because of a slim majority then it will spark a leadership contest to decide who will replace her at the helm of the Conservative party and become the next prime minister. This would be a swift process lasting just two weeks, when contenders would campaign to win endorsement from their party colleagues.

Would there be a general election if May loses the vote?

The government is not required to hold a general election if May loses the vote of no confidence and can elect a new prime minister without asking the public. The opposition Labour party’s official Brexit position is that there should be a general election as a way of securing a mandate from the public on Brexit as well as wider issues in the hope they can take over negotiations with the EU. Although Jeremy Corbyn’s party cannot demand a general election they can pressure the government by convincing the public it is in their interests.

If May loses then the immediate question is who will be the next leader of the Conservatives and the next prime minister of the UK. But the follow-up question is whether the government can justify installing a second consecutive unelected leader - the public had no say in May’s rise to the top after she took over following David Cameron’s resignation after ‘losing’ the EU referendum vote. Unsurprisingly, the Conservatives that have risked this say they have lost faith in May but not the government – a claim that many will find hard to believe.

The latest odds from Ladbrokes have odds of 11:8 on a general election being called in 2019, with March (when Brexit is due) to May tipped to be the most likely period for a public vote to be held.

Why has a vote of no confidence been called?

The Conservative MPs that have launched the challenge against May are mostly Brexiteers and unhappy with the way she has handled Brexit. The vote of no confidence is the consequence of the underlying debate over how a prime minister that voted to Remain can truly deliver the Brexit that Leave supporters voted for.

There is not currently a majority in the House of Commons for any Brexit scenario on the table but there is agreement that May’s withdrawal deal does not work. This is mainly because of the Irish backstop issue that, in its current form, would leave Northern Ireland in a customs union with the EU indefinitely.

Read more: What are the pros and cons of leaving the EU?

Although the Conservatives challenging May want her out there is no current alternative on the table. No aspirational MPs have formally thrown their hat into the ring or explained how it would solve the division over Brexit in the House of Commons. When May pulled the vote on her Brexit deal despite the EU making it clear there is 'no room whatsoever for renegotiation' many MPs asked how she thought changing minor details would swing their vote. That was a fair question and May is now using it to her own advantage, stating a change of leader 'does not change the fundamentals or parliamentary arithmetic.'

Read more: Juncker says no to renegotiation of Brexit

May is struggling to unite her party at such a crucial time but it doesn’t look like there is anybody else who can heal all the open wounds. Some of those who have submitted letters of no confidence believe the UK should simply leave the EU with no deal and withhold the £39 billion divorce bill while others think there is still time to renegotiate a new deal. The hardest of Brexiteers contest that this will mean Article 50 will have to be extended because there would not be enough time to elect a new prime minister before the 21 January deadline and claim that they would fast-track a vote to have a leader in place by the new year.

Still, it is very optimistic to think the Brexit deal can be renegotiated by a new leader in less than a month and the EU is unlikely to change its tune so late in the day. This is why many smell political ploys: many Brexiteers want a no deal and, because this is the default position, are simply ticking down the clock so the UK crashes out of the EU without a deal or transition period.

Read more: Is the UK drifting into a no deal?

Those Conservatives preparing to launch a leadership bid will have to rapidly formulate a cohesive plan that explains how voting them into power would address the deeply divisive issues that will remain unresolved whether May is ousted or not.

Who will be the prime minister after Christmas?

There is a long list of potential Conservative MPs that could compete to become the new leader of the party, and therefore prime minister, should May lose the vote of no confidence. Ambitious Conservatives with an eye on the top job are highly unlikely to announce their bids unless May is ousted or resigns. Interestingly, some of the favourites to succeed May have announced their support for the prime minister such as foreign secretary Jeremy Hunt and home secretary Sajid Javid. But voting in favour of May doesn’t mean an MP won’t try to take her job if she leaves anyway.