Betting odds on who is going to be next Prime Minister

Quite simply, the job proved to be too much for Ms Truss, who Tory members voted in as leader over the summer chiefly because she wasn’t Rishi Sunak.

The race to replace her is already underway and the billionaire former Chancellor appears to be in pole position.

He lost out in the leadership contest by a margin of nearly 21,000 votes, with many members opposing him over his prominent role in toppling Boris Johnson.

Mr Sunak was however, favoured by a majority of MPs in the parliamentary part of the race, suggesting he would have a big chance should Ms Truss’s successor be elected solely by MPs.

His stock is also likely to have risen in light of the dire – and mostly accurate – economic forecasts he made in August, when he warned his opponent’s widespread tax cuts were “fantasy economics”.

New Chancellor Jeremy Hunt is next in the betting, although he's reportedly ruled himself out. A staunch Remainer, he received plaudits for his performance in the Commons this week simply for speaking in a calm manner and not making a fool of himself.

So low is the bar. Mr Hunt was bombed out of the leadership contest early doors having come second to Mr Johnson in the 2019 election.

He does have pockets of support on a local level, most notably from West Midlands Mayor Andy Street. Lord Cormack, the former South Staffordshire MP, is another fan.

He said in the Lords this week: “What is crucial at the moment is that in the country as a whole there should be real confidence in the credibility and the competence of the Government, and that that means there has to be a Prime Minister who is entirely credible and who enjoys the full confidence of the country, as I believe the Chancellor now does.”

Penny Mordaunt is also highly fancied, with speculation growing in recent days that the current Leader of the House may join forces with Mr Sunak on a joint ticket that would have looked highly improbable a few weeks ago.

Ms Mordaunt ended up backing Ms Truss over the summer having narrowly lost out to her rival for a place in the final two. She remains a popular figure among some Tory MPs, although her views on trans rights have not sat well with those to the right of the party.

Labour leader Sir Keir Starmer is behind only three Tories in the betting. He was polling favourably even before this week’s chaos, and will now see a clear path ahead of him to Number 10.

Although he has repeatedly called for a general election, would Sir Keir really want to become PM with the country in its current state? He has done an adequate job of sniping from the sidelines and calling out the Government’s obvious failings, but it is highly questionable whether he has what it takes to lead the country at this perilous time.

In his favour he does have a frontbench containing MPs with experience of government, including Wolverhampton South East MP Pat McFadden, Yvette Cooper and Ed Miliband. But how will he fare when his policies are actually put to the test?

For many Tories, Defence Secretary Ben Wallace would be a popular choice.

He ruled himself out of the last leadership election having stayed loyal to Mr Johnson to the very end. But he appears to have had a change of heart.

When asked at the recent Conservative Party conference in Birmingham if he would consider running for leader, he said: “I don’t rule it out.”

Some consider him to be one of the few figures capable of bringing some form of unity to the party, although his support for Remain during the EU referendum will rankle with some.

One figure looming large over every possible scenario is Mr Johnson.

If there was a vote among members tomorrow, the former PM would win by a landslide.

But many of the Tory MPs who booted him out just a few weeks ago over Partygate and the Chris Pincher scadal would be loathe to welcome him back into the fold at the first sign of trouble.

It is also unlikely that Mr Johnson himself would consider a return under the current circumstances.

Since his departure public support for the Tories has collapsed and he may well view the task of getting the Government back on track to be too much of a challenge.

The new president of the Conservative Friends of Ukraine group is sure to have no shortage of offers on the highly lucrative political speech circuit, which may seem like a more attractive option at the moment.

Naturally, he does have his supporters in the Commons.

They include Lichfield MP Michael Fabricant, who this week revealed in the Star that he had written to Sir Graham Brady suggesting Mr Johnson would be the only rightful successor to Ms Truss.