Sunak v Mordaunt in a crucial day in the Tory leadership race

Today Tory MPs will choose who they want to be their new leader - and next Prime Minister - after Boris Johnson dramatically pulled out of the contest to replace Liz Truss who resigned last week.

The ex-PM claimed he had enough nominations needed to make it onto the ballot paper but admitted he could not unite his warring party.

His withdrawal means the contest could be decided by early afternoon on Monday unless both the remaining candidates can get the support of 100 MPs.

In a statement on Sunday evening, Mr Johnson said there was a "very good chance" he could have been back in No 10 by the end of the week if he had stood.

However his efforts to "reach out" to his rivals - Rishi Sunak and Penny Mordaunt - to work together in the national interest had not been successful so he was dropping out.

Here's what we know about the two rivals for Number 10:

Rishi Sunak

Former chancellor Rishi Sunak heads into the race this week confident that he has the backing of enough MPs to make it onto the ballot paper.

He was defeated just seven weeks ago in the last Tory leadership race as the party membership picked rival Liz Truss, garnering 60,399 votes to her 81,326.

In that contest, he positioned himself as the candidate prepared to tell hard truths about the state of the public finances rather than "comforting fairy tales".

He remained resolute in the view that his rival's promises of unfunded tax cuts at a time of worsening inflation were irresponsible, dangerous and un-Conservative, predicting that they would lead to surging mortgage rates.

After Ms Truss took office, her disastrous mini-budget triggered turbulence in the financial markets and forced the Bank of England to intervene, proving Mr Sunak right.

He kept a low profile as the chaos continued, staying away from the annual Tory conference, which was overshadowed by a U-turn on a flagship policy to scrap the 45p rate of income tax.

Accusations in the last leadership race that he represented "Treasury orthodoxy" and a "gloomster" mentality could speak in his favour this time, as many will be reassured by his undoubted experience in handling the economy and his realist approach.

The ex-chancellor gathered a string of endorsements from MPs before declaring he would run, with backers highlighting his "calm competence" and portraying him as a "serious person for serious times".

Penny Mordaunt

Leader of the House Penny Mordaunt will need to receive a tidal wave of support to reach the requisite 100 nominations on Monday.

She finished third in the last leadership election, failing to receive enough backing from MPs to qualify for the membership vote.

She opted to back Ms Truss, and was rewarded with a role in the new Cabinet, taking up the reins as Commons Leader.

Her initial bid for the top job triggered some excitement, as colleagues rallied behind a fresh face to lead the Conservatives.

But her dearth of ministerial experience at that stage became a weakness that her rivals sought to exploit, even if she appeared to remain a popular choice among the party membership.

She will now be able to cite her tenure as Commons Leader - albeit short-lived - as she sets her sights on Downing Street once more.

Ms Mordaunt will inevitably be tied to the Truss premiership to some extent, as she served in the Cabinet during the PM's tumultuous period, which saw market chaos at one stage threaten to trigger a financial crisis in the UK.

However, she has hardly been conspicuous in her loyalty, making it clear she believed benefits should rise in line with inflation at the Tory conference earlier this month, despite Ms Truss repeatedly refusing to guarantee the boost.

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• penny mourdant