Jeremy Corbyn has urged opposition leaders and Tory rebels to install him as caretaker prime minister to stop a no-deal Brexit.
If he wins a no-confidence vote in the Government in September, the Labour leader plans to delay Brexit, call a snap election and campaign for another referendum.
The offer prompted a bout of infighting after the Liberal Democrats said they would not support any moves to put Mr Corbyn in Number 10.
In a speech yesterday, Lib Dem leader Jo Swinson called Mr Corbyn “divisive” and said: “We are facing a national crisis. We may need an emergency government to resolve it. But if Jeremy Corbyn truly wants that to succeed, surely he can see he cannot lead it.
“There is no way he can unite rebel Conservatives and independents to stop Boris Johnson. It’s not even certain he could secure all the votes of Labour MPs. This isn’t about personalities, this is about having a plan that actually works.”
In his letter to opposition leaders, Mr Corbyn wrote: “This government has no mandate for no-deal, and the 2016 EU referendum provided no mandate for no-deal.
“I therefore intend to table a vote of no confidence at the earliest opportunity when we can be confident of success.
“Following a successful vote of no confidence in the government, I would then, as leader of the opposition, seek the confidence of the House for a strictly time-limited temporary government with the aim of calling a general election, and securing the necessary extension of Article 50 to do so.”
The comments were welcomed by Green Party MP Caroline Lucas, who urged Ms Swinson to reconsider Mr Corbyn’s “reasonable” offer.
First Minister Nicola Sturgeon also welcomed the move and committed the SNP to backing Mr Corbyn in any coalition against no-deal.
She said: “We’ve made clear all along that we will work with anyone in Westminster to try to stop Brexit and avert the catastrophe of a no deal Brexit.
“I think the best thing in a Westminster context would be a for a general election or second referendum to give people the opportunity to change tack, but we’ll work with anybody.
“But Jeremy Corbyn has to finally and firmly come off the fence on Brexit and stop trying to prevaricate.
“I’m not a great fan of Jeremy Corbyn, but we won’t rule out anything to if it helps to avert the catastrophe of a no-deal Brexit.”
A Downing Street spokesman hit out at the plan, saying: “This Government believes the people are the masters and votes should be respected, Jeremy Corbyn believes that the people are the servants and politicians can cancel public votes they don’t like.”