Senior Tory Ken Clarke and former deputy Labour leader Harriet Harman are both prepared to lead an emergency government to avoid a no-deal Brexit, Lib Dem leader Jo Swinson has said.
Ms Swinson rejected Jeremy Corbyn’s proposal that he should be caretaker PM if he wins a vote of no confidence in Boris Johnson’s government.
She said the Labour leader did not have enough support from MPs.
Mr Corbyn said he was “ready to serve” as PM if the government collapsed.
Speaking on a visit to Machynlleth, Powys, he said he was “disappointed” by Ms Swinson’s response to his plan, adding that he hoped she would “come round” to it.
Asked if he could support Mr Clarke or Ms Harman as an interim prime minister, Mr Corbyn said: “Under normal constitutional processes in Britain, when a government collapses, the leader of the opposition is called on to form a government.”
It was “not up to Jo Swinson to decide who the next prime minister is going to be”, he added.
Ms Swinson put forward Mr Clarke and Ms Harman – who are the longest-continuously serving male and female MPs – as potential caretaker prime ministers, saying they were both experienced and command respect across Parliament.
“I have been in touch with them because obviously you don’t just mention people’s names without checking that they’re OK with that,” she told BBC Radio 4’s Today programme.
“They put public duty first and they don’t want to see a no-deal Brexit,” she added.
“If the House of Commons asks them to lead an emergency government to get our country out of this Brexit mess and to stop us driving off that cliff to a no deal, then yes, they are prepared to do that.”
However, Ms Swinson said she would be open to discussing alternative suggestions with Mr Corbyn of installing “an experienced MP who has that respect across the House”.
On Thursday, Mr Corbyn set out his plan to prevent a no-deal Brexit, which involves calling a vote of no confidence in the government and – if that is successful – a snap election, where he would campaign for another referendum.
The SNP and Plaid Cymru did not rule out supporting a cross-party government to stop a no-deal exit and some Tory rebels suggested they would hold talks with Mr Corbyn.
An SNP spokesman confirmed the party’s Westminster leader, Ian Blackford, had held a “constructive conversation” with the Labour leader on Friday morning to discuss “ways in which the opposition parties can work together in removing the growing threat of a disastrous no-deal Brexit”.
Conservative former minister Guto Bebb said MPs should “take seriously” the offer, arguing that a short-term Mr Corbyn government would be “less damaging than the generational damage that would be caused by a no-deal Brexit”.
But David Gauke – a former justice secretary – signalled his opposition to the plan, tweeting: “If anyone thinks the answer is Jeremy Corbyn, I think they’re probably asking the wrong question.”
Senior Tory Remainer Dame Caroline Spelman and the Independent Group for Change also refused to support a Corbyn government.
Prime Minister Boris Johnson has said he wants a deal with the European Union, but insists the UK must leave the bloc by the end of October “do or die”.
He has also said the cost of a no-deal Brexit would be “vanishingly inexpensive, if you prepare”.
Business Minister Kwasi Kwarteng said he was “a great fan” of Mr Clarke, but dismissed talk of the MP becoming prime minister as “speculation” – adding that he did not believe Labour could win a no-confidence vote.
Who are Ken Clarke and Harriet Harman?
Ken Clarke was first elected to Parliament as a Conservative MP in 1970 for the Nottinghamshire constituency of Rushcliffe.
He held several senior government posts under Margaret Thatcher and John Major, including health secretary, education secretary and chancellor.
However, his pro-European stance put him at odds with many in his party and despite three attempts in 1997, 2001 and 2005, he failed to become Conservative leader.
Harriet Harman was first elected to the London constituency of Peckham in 1982.
Under Tony Blair’s government, she served as social security secretary, minister for women and solicitor general.
In 2007 she won the race to be deputy leader of her party, and became acting leader in 2010 when Gordon Brown resigned following Labour’s general election defeat.