BOOKMAKERS are tipping the Prime Minister to win tonight’s showdown.
But in case she doesn’t, here are some of the runners and riders who might enter the Tory leadership race.
Prominent Brexiteer and former Foreign Secretary, Mr Johnson (joint favourite at 4-1 with William Hill and Ladbrokes) is a leading voice of opposition to Mrs May’s Brexit plan.
The colourful Old Etonian was one of the key players in the 2017 Leave campaign and resigned from the cabinet following the Chequers summit in July.
He was heavily tipped as a successor to David Cameron but ruled himself out of the 2016 leadership contest after Michael Gove made a last-minute bid for the top job.
In a diary piece for the Spectator, Mr Johnson compared his former “late night binges of chorizo and cheese” and recent weight loss to Brexit: “We know that we have to make certain changes if we are to leave the EU.”
Mr Johnson refused to rule out challenging Theresa May in at interview at the weekend, saying the British people should not “underestimate the deep sense of personal responsibility I feel for Brexit”.
Father-of-four Mr Johnson, 54, who was Mayor of London for eight years, recently announced his divorce from his wife Marina Wheeler, a human rights lawyer.
Former Brexit Secretary Mr Raab (joint favourite with Boris Johnson at 4-1 with Ladbrokes or 5-1 with William Hill) has refused to rule out standing in a leadership contest.
Mr Raab, a prominent Brexiteer in the referendum campaign, was appointed as Brexit Secretary in July but resigned from the role in November, saying he could not support Mrs May’s eventual deal.
In his resignation letter on November 15, he wrote: “Ultimately, you deserve a Brexit Secretary who can make the case for the deal you are pursuing with conviction. I am only sorry, in good conscience, that I cannot.”
Mr Raab, 44, has been the MP for Esher and Walton since he was elected in 2010.
The son of a Czech-born Jewish father who came to Britain in 1938, he is married with two children.
In his interview with the Spectator, Mr Javid signalled his leadership ambitions by arguing that he wanted the Tories to be the party of social mobility.
The odds on Javid taking the top job are currently 6-1, according to Ladbrokes, or 11-2 with William Hill.
He didn’t stand in the 2016 leadership race but has since emerged as one of the favourites in Westminster to succeed Mrs May.
Javid, 49, who backed Remain in the referendum but has since positioned himself as a firm Leaver, became the first home secretary from an ethnic minority background when he was appointed in April 2018.
The son of a Pakistani bus driver from Rochdale, he was a managing director at Deutsche Bank before becoming an MP in 2010. He is married with four children.
Foreign Secretary Jeremy Hunt (odds 8-1 with Ladbrokes or 7-1 with Paddy Power and William Hill) was a prominent Remainer in the 2016 referendum.
As Health Secretary, Mr Hunt fought a long battle with doctors over a new contract.
He was appointed Foreign Secretary in July following the resignation of Boris Johnson.
He chose not to run in the 2016 leadership contest and instead gave his full support to Mrs May, saying it was “not the right time” to put his hat in the ring.
Mr Hunt tweeted his support for Mrs May on Wednesday morning, admitting “Brexit was never going to be easy” but adding that she was the “best person to make sure we actually leave the EU on March 29”.
The 52-year-old was first elected as MP for South West Surrey in 2005 and has held a number of positions in the Cabinet since then.
He is married to Lucia Guo, who was born in Xian in central China, and they have three children. During a recent trip to China he dropped a clanger by saying his wife was Japanese instead.
Prior to the 2016 referendum Jacob Rees-Mogg was a relatively little-known backbench MP.
But following his criticisms of the Brexit negotiations and Mrs May he has emerged as popular figure with Leave-backing Conservatives.
Despite not being a Cabinet minister, William Hill is offering odds of 12-1 (16-1 with Ladbrokes) that he will become the next leader of the Conservative party.
The arch-Brexiteer led figures from the European Research Group of Tory MPs – which he heads – calling for backbenchers to trigger a leadership challenge.
The North East Somerset MP wants a “managed no deal” and has turned up the heat on Mrs May by repeatedly insisting a new leader would be needed for such a course of action.
Another Old Etonian, Mr Rees-Mogg, 49, was elected in 2010. Before that, he co-founded a hedge fund management business.
A devout Catholic, he is married with six children.
Secretary of State for International Development Penny Mordaunt is on 12-1 with William Hill, or 25-1 with Ladbrokes.
A prominent Leave campaigner, there was speculation she might resign over Mrs May’s Withdrawal Agreement and she was named by Jacob Rees-Mogg as one of his favoured candidates.
But Ms Mordaunt has publicly voiced her support for Mrs May in recent months although she has not ruled out putting herself forward should the Prime Minister lose a vote of no confidence.
She pledged her support for Andrea Leadsom in the 2016 Conservative leadership contest.
Ms Mordaunt, 45, has been an MP for Portsmouth North since 2010 and is a Royal Navy reservist.
In 2014, she appeared on reality TV show Splash!
Michael Gove (joint third with Jeremy Hunt at 8-1 with Ladbrokes) appeared to rule himself out of the running in recent days.
With other senior members of the Cabinet reportedly manoeuvring to replace Mrs May if she had lost Tuesday’s ultimately postponed Commons Brexit vote, Mr Gove said it was “extremely unlikely” that he would stand as a future Conservative Party leader.
That apparent reluctance could have something to do with his previous bruising experience in a Tory leadership race.
In June 2016, Mr Gove, who was campaign manager for Boris Johnson’s drive to succeed David Cameron, withdrew his support on the morning that Mr Johnson was due to declare and threw his own hat in the ring instead.
He came third in the first round of voting, trailing behind ultimate winner Theresa May and Andrea Leadsom.
Mr Gove, 51, was born in Edinburgh, studied English at Oxford and was a journalist before becoming an MP. He is married to Daily Mail columnist Sarah Vine.
The original Brexit Secretary, David Davis (joint with Amber Rudd on odds of 16-1 according to Ladbrokes and 14-1 with William Hill) has been publicly critical of the withdrawal agreement proposed by Mrs May.
He plunged the Government into crisis after he resigned from the Cabinet in July over the Chequers deal, followed out the door by fellow Department for Exiting the EU minister Steve Baker.
The long-term Leaver has echoed other Tory Eurosceptics in saying the Prime Minister’s Withdrawal Agreement was worse than staying in the EU, adding “neither is a good option”.
Mr Davis has not not ruled out standing for the Tory leadership if Mrs May loses the vote of no confidence.
He was a candidate for leadership in 2001, when he came fourth, and in 2005, when he came second to the former Prime Minister David Cameron.
A former SAS reservist, Mr Davis, 69, has been the MP for Haltemprice and Howden since 1997. He is married with three children.
Amber Rudd made a return to the Cabinet as Secretary of State for Work and Pensions in November after her resignation as Home Secretary earlier this year following the Windrush scandal.
She appeared to rule out a leadership bid ahead of Tuesday’s postponed vote and pledged “huge support” to Mrs May, but both William Hill and Ladbrokes have her at 16-1, ahead of some other Cabinet ministers.
Earlier this week, Ms Rudd hit out at male Tory Eurosceptics who “seem to flounce out quite a lot” in a wide-ranging interview with The Times.
The Remainer has said she wouldn’t rule out a second referendum but has openly favoured a Norway Plus model, which involves staying in the European Economic Area.
Ms Rudd, 55, became MP for Hastings and Rye in 2010. She had two children with her former husband, the writer and restaurant critic A A Gill, who died in 2016.
Cabinet Office minister and de facto deputy Prime Minister David Lidington tweeted his support for Mrs May on Wednesday.
Mr Lidington has not signalled he would make a bid to be leader should Mrs May lose the vote of no confidence.
But William Hill is offering odds of 16-1 on him being her successor.
The 62-year-old has been the MP for Aylesbury since 1992 and was Minister of State for Europe from 2010 to 2016. He is married with four children.
Leader of the Commons since June, Andrea Leadsom found herself at the centre of controversy in the 2016 leadership campaign when comments she made were interpreted as a claim that she would be a better PM than Mrs May because she was a mother.
Asked recently whether Mrs May was the right person to be leading the country, she said she is “at the moment”.
She has previously refused to rule out another leadership bid in the future. William Hill rate her at 20-1.
Mrs Leadsom, 55, is married with three children. She has been the MP for South Northamptonshire since 2010 and has held a number of Cabinet roles.
Attorney General Geoffrey Cox is also rated at 20-1 by William Hill.
He won a lot of fans during the row over publishing the Government’s legal advice about the Withdrawl Agreement when he told MPs to “grow up and get real”.
Mr Cox was appointed a Queen’s Counsel in 2003 and became the MP for Torridge and West Devon in 2005.
He is married with three children.
Former Work and Pensions Secretary Esther McVey handed in her resignation letter minutes after Mr Raab stepped down in July, saying Mrs May’s Brexit deal did not “honour the result of the referendum”.
She has not ruled out putting her hat in the ring for a future leadership contest.
One of the few Brexit-backing women in the Tory ranks, William Hill puts her odds at 20-1, alongside Mrs Leadsom and Mr Cox.
A former breakfast TV presenter who worked alongside Eamonn Holmes on GMTV, the 51-year-old has been MP for George Osborne’s old seat Tatton since 2017.
Before that she was the member for Wirral West from 2010 but lost her seat to Labour in 2015.
Defence Secretary Gavin Williamson was promoted from Chief Whip in 2017 following the resignation of Sir Michael Fallon.
In his former role as Tory enforcer, he kept a tarantula on his desk.
He backed Remain in the referendum and pledged his support for Mrs May in the 2016 leadership contest but has since been mentioned as a potential future Tory leader.
Mr Williamson’s delay in openly backing Mrs May on Wednesday raised suspicions he could be pondering a bid.
But he subdued this by tweeting: “The Prime Minister has my full support. She works relentlessly hard for our country and is the best person to make sure we leave the EU on 29 March and continue to deliver our domestic agenda.”
Ladbrokes put Mr Williamson’s chances of being the next Conservative leader at 50-1, well behind other cabinet ministers.
The 42-year-old became MP for South Staffordshire in 2010. He is married with two children.
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