The list of runners and riders to replace Mr Johnson has fluctuated over recent months, but there are several contenders should he eventually be forced out of 10 Downing Street.
According to Betfair, Mr Johnson is odds-on at 5/6 to leave No 10 this year.
The chancellor has seen his fortunes decline amid the fallout from revelations in The Independent about his family’s tax status.
But bookies have not fully turned against Mr Sunak, who remains in the top five MPs most likely to take over the reins from Mr Johnson, wth odds of 9/1.
The 42-year-old was once a favourite, at least in part due to his pandemic payouts, but he has since has been criticised for being slow to react to rising energy bills and not doing enough to help the poorest households.
According to Betfair Exchange, Jeremy Hunt, the former health secretary, is now the favourite to replace the PM on 9/2.
Mr Hunt, who has also served as foreign secretary, has been very visible in the media of late, giving interviews to a number of outlets, talking about his new book and the future of the Conservative Party. He recently warned his colleagues that the Tories have a “big mountain to climb” if they are to win the next general election following the Partygate scandal.
Mr Hunt, who came second to Mr Johnson in a 2019 leadership contest, refused to rule out another tilt at the top job but cautioned that it was not the right time for a leadership contest due to the war in Ukraine.
“But I would be very open with you that I don’t rule out a return in the future,” he added.
Liz Truss, long touted as a future leader, is in second place on odds of 7/1.
The foreign secretary and MP for South West Norfolk, saw her stock rise after building a reputation as someone who could get a job done, securing a series of mini trade deals during her tenure as international trade secretary.
“Fizz with Liz” had been a phrase associated with the foreign secretary amid reports earlier this year that she hosted MPs in her parliamentary office in a bid to schmooze possible backers.
Her threats to overwrite parts of the controversial Northern Ireland protocol as well as her sanctions response to Russia over Ukraine went down well with some Conservative backbenchers.
More recently, however, Downing Street has moved to distance itself from the foreign secretary’s harsh rhetoric on the protocol and she has been criticised for what some have described as leadership posturing during a crisis.
The MP for Tonbridge and Malling and chair of the foreign affairs committee whose stock has steadily risen in recent weeks, is in third place on 8/1.
Mr Tugendhat became the first to announce he intends to stand for leader should Mr Johnson be given the boot, making his declaration in January.
The former soldier said: “I think I’m making it pretty clear that I think that it’s up to all of us to put ourselves forward. And it’s up to the electorate, in the first case parliamentary colleagues, and in the second case the party, to choose.
“I think it’s a position of absolute integrity to say that of course you should offer yourself to the electorate if you think you can do it. Of course you should talk to colleagues and see if you can get a group together, and if you can get a group together you should go for it.”
Mr Tugendhat’s ambitions might not be supported by everyone in the party, but they could secure him a plum job in a future cabinet.
He shares third place with Penny Mordaunt, the MP for Portsmouth North and international trade minister and a key figure in the 2016 Leave campaign in the EU referendum.
Ms Mordaunt might be viewed as an outside bet but she is likely to attract support. Her recent work has included leading efforts to secure economic pacts with American states and she is considered a strong speaker and on top of her brief in her Commons appearances.
Ben Wallace, the defence secretary who has been widely praised for his performance during Vladimir Putin’s invasion of Ukraine, who is on 12/1.
He has won admirers in Westminster for his straight-talking and straight-forward approach to politics, particularly among Tory MPs who pressed for the UK to increase its defence spending although cuts to the size of the army remain a cause for concern.
Mr Wallace, who served in the Scots Guards, remains a key voice in the UK’s response to Russia’s renewed invasion of Ukraine and this increased exposure could assist any leadership bid.
Nadhim Zahawi, the education secretary and MP for Stratford-on-Avon, is second from bottom on BetFair’s list on 17/1.
The health secretary, and Bromsgrove MP is on 19/1. His frontline political future was in doubt when he quit as chancellor in February 2020 just six months into the job after No 10 told him to sack all of his advisers. But Mr Javid has bounced back since June 2021 as health secretary.
In the 2019 leadership contest, he proposed cutting the top rate of income tax and he was also reported last month to be among those against a windfall tax on oil and gas producers.
With some in the party calling for lower taxes, this could chime with Mr Javid’s instincts and help boost his chances.
Full list of odds:
Betfair: Boris Johnson to win Vote of Confidence
Betfair Exchange: Boris Johnson exit date
2022: 5/6 (was 5/4 last week)
2024 or later: 2/1
Betfair Exchange: Next Conservative leader after Boris Johnson
Jeremy Hunt: 9/2
Liz Truss: 7/1
Tom Tugendhat: 8/1
Penny Mordaunt: 8/1
Rishi Sunak: 9/1
Ben Wallace: 12/1
Nadhim Zahawi: 17/1
Sajid Javid: 19/1