Senior Nationalists are concerned there is little time left before the October 31 deadline when the UK is scheduled to leave the EU to agree on a compromise candidate to replace Boris Johnson, if the Tory leader was forced from office by a vote of no confidence.

Following mounting speculation on Friday, the First Minister said she agreed with the idea of installing the Labour leader, or another candidate, as a caretaker prime minister.

Boris Johnson slams ‘inadequacies’ of SNP record in power

The First Minister tweeted on Friday that she agrees with the idea of installing the Labour leader as PM

She later clarified that she was “open minded” about who entered No 10 if Mr Johnson was forced from office.

But the Scottish Conservatives warned that any deal between Labour and the Nationalists would inevitably involve an agreement to hold a second independence referendum.

The SNP leader agreed that a new PM would be required following a vote of no confidence in Mr Johnson’s minority administration. They could then request a Brexit extension before calling an immediate general election.

However, the plan would require support from other opposition parties in the Commons as well as the SNP to pass, including 23 MPs expelled by the Tories.

Jeremy Corbyn has so far refused to back calls for a general election

The Liberal Democrats insisted that the numbers did not add up for Mr Corbyn to take over as prime minister.

Mr Corbyn is reportedly due to meet other opposition leaders to discuss tactics on Monday after Ms Sturgeon’s test of the fragile coalition operating to prevent a no-deal Brexit.

Former Scots Tory leader Ruth Davidson said: “Let’s take a guess at what the SNP’s price would be for installing Corbyn in No 10. We know from John McDonnell that Labour would happily hand them IndyRef2 on a plate.”

In response to a tweet making the suggestion that Mr Corbyn could enter No 10 to halt no deal, Ms Sturgeon said: “Agree with this. VONC (vote of no confidence), opposition unites around someone for sole purpose of securing an extension, and then immediate General Election.

“Nothing is risk free but leaving Johnson in post to force through no deal - or even a bad deal - seems like a terrible idea to me.”

Prime Minister Boris Johnson has maintained Britain will leave the EU on October 31, with or without a deal.

The Benn Act, passed in Westminster earlier this month, instructs the PM to request an extension to the deadline until the end of January if no deal is agreed, but that is something Mr Johnson has repeatedly said he will not do.

Ms Sturgeon later tweeted: “The point I’m making is not really about who it should be - I’m open minded on that - more that the opposition needs to unite behind a plan and act.”

A spokesman for the SNP said: “The SNP has led the way in ensuring Brexit can be stopped and in bringing Parliament back into action after the Tories sought to shut down UK democracy, and we will continue to work with all opposition MPs to stop a no-deal Brexit and call a general election to remove this dangerous and undemocratic Prime Minister as soon as possible.

“It is now possible - if the political will is there - that parties could come together to ensure that the letter to secure an extension is not left in the hands of Boris Johnson and his cronies, who are determined to find a way to get around the Benn Act, but is instead sent by a temporary caretaker prime minister, who would be in office only as long as is necessary to send the letter, with an election held immediately afterwards.

“We remain open to all options to achieve the aim of stopping a no-deal Brexit and getting rid of Boris Johnson.”

Scottish Liberal Democrat spokeswoman for constitutional relations Wendy Chamberlain said: “We need a plan that has a whiff of a chance of working. Liberal Democrats will back a temporary government to stop a no-deal Brexit but that cannot be led by the divisive Jeremy Corbyn.

“The numbers don’t add up. Even Nicola Sturgeon has said that she doesn’t trust him.

“Jo Swinson is working hard across parties to build a majority at Westminster to stop the damage of Brexit. Anyone who wants to keep Scotland in the UK and the UK in the EU should vote for the Liberal Democrats.”

Kirstene Hair, Conservative MP for Angus, said: “This confirms what many have long suspected - SNP MPs will happily prop up Jeremy Corbyn in Number 10.

“There is no doubt that Corbyn’s weak stance on IndyRef2 is a deciding factor for the nationalists.

“He has already left the door open for a re-run of the 2014 referendum if he becomes prime minister.

“Only a Conservative Government will stand up for those who voted No in what was meant to be a once-in-a-generation event.”

Earlier on Friday, a senior SNP source told ITV News: “It is increasingly clear that we will have to install a new prime minister via a vote of no confidence, so that we can request a delay to Brexit and hold an election,” a party source told

“The convention is absolutely clear that it is the leader of the opposition - in this case Jeremy Corbyn - who should become prime minister in those circumstances.

“Trying to find a compromise candidate, a national unity candidate, is too complicated, especially in the time we have. Whether people like it or not, the temporary prime minister has to be Corbyn.”

The source added that the other opposition parties, and the 34 independent MPs, would have to come round to backing Corbyn, if they want to be certain of avoiding a no deal Brexit.

Lib Dem leader Jo Swinson has repeatedly said she would not support any deal that saw Mr Corbyn become PM.

Nicola Sturgeon has previously claimed her party would explore all options to ensure the UK did not crash out of the EU.

“I’ve said all along we would work across the parties to try and put a coalition together in Westminster to preferably stop Brexit altogether, but absolutely to stop a no deal Brexit,” she said last month.

SNP would back plan to install Jeremy Corbyn as temporary prime minister to halt no deal