Tory grandee Ken Clarke has said he is willing to become a caretaker Prime Minister to avoid a no deal Brexit in a challenge to Boris Johnson’s leadership.

The former chancellor and longstanding MP gave his support to a proposal by Liberal Democrat leader Jo Swinson to lead an emergency government “to sort Brexit out”.

Likening the current political situation to 1931 and the two world wars, Mr Clarke said it was “not inconceivable” that a cross-party coalition would be needed to break the impasse.

"If they ask me to lead, yes I would lead it,” he said. “If it was the only way in which the plain majority in the House of Commons that is opposed to a no-deal exit could find a way forward, I wouldn't object to it."

Mr Clarke - known as the Father of the House, a title bestowed on the longest-serving male MP - said such an administration would be a "single-issue, short-term government", insisting the parties could return to their “old tribalism” afterwards.

At 79, he would become the oldest Prime Minister to take office in history at nearly a decade old than Lord Palmerston, who was 70 when he was appointed in 1855.

Revealing he had only recently found out he had been touted for the role after returning from a two week summer holiday in Norway, Mr Clarke, said: “But there's an awful lot to be gone through before then and I haven't been taking part in any talks with anybody for the last fortnight. I've been on the phone to one or two people in the last couple of days just to find out what the devil's going on."

Ms Swinson's proposal came after she rejected Labour leader Jeremy Corbyn's suggestion that he could lead an emergency government to thwart a no-deal Brexit, along with Tory rebels and some Labour MPs.

On Friday night, Liberal Democrat sources said there was some opposition to Mr Clarke’s suggestion that he would seek to try to renegotiate another deal with the EU rather than call a second referendum to block Brexit altogether.

“Personally I think a negotiated deal is the one that would carry the majority of the House of Commons and help reunite the public but I’m open to arguments about a referendum,” Mr Clarke said.

“There are remainers, including myself, prepared to compromise, who would go for a soft Brexit staying in the single market and customs union and there are hardline remainers who won't have anything but a people's vote which they are sure is going to reverse their decision and keep us in the European Union.”

What’s App messages exchanged among Lib Dem supporters, seen by the Daily Telegraph, suggested dissent in the ranks. One said: “How can the Lib Dems support that?” Another featured a picture of Ms Swinson alongside the caption: “No deal enabler”.

Ms Swinson had already come under fire for first branding Mr Corbyn’s plan ‘nonsense’ before agreeing to hold talks with him.