Philip Hammond has warned that MPs will topple any new Tory prime minister trying to force through a no-deal Brexit – and sensationally threatened to join the revolt himself.

The chancellor refused – three times – to rule out joining the no-confidence vote that Labour has vowed to table if a hardline Brexiteer succeeds Theresa May.

Mr Hammond said any new leader trying to “push through a no-deal exit on 31 October” would immediately face the prospect of having to “leave office”.

“It would be very difficult for the prime minister who adopted no-deal as a policy to retain the confidence of the House of Commons,” he said – just minutes after Dominic Raab made that exact threat.

Asked if he would support a no-confidence motion, Mr Hammond told the BBC’s Andrew Marr it was “hypothetical”, pointing out he had never voted against his party in 22 years.

But he added: “I don’t want to start now having to contemplate such a course of action.”

EU elections 2019 Europewide results Show all 9 1 /9 EU elections 2019 Europewide results EU elections 2019 Europewide results European People's Party group MEPs: 182 Vote share: 24.2% EU elections 2019 Europewide results Progressive Alliance of Socialists and Democrats MEPs: 147 Vote share: 19.6% EU elections 2019 Europewide results Alliance of Liberals and Democrats for Europe group MEPs: 109 Vote share: 14.5% EU elections 2019 Europewide results Greens–European Free Alliance MEPs: 69 Vote share: 9.2% EU elections 2019 Europewide results European Conservatives and Reformists MEPs: 59 Vote share: 7.9% EU elections 2019 Europewide results Europe of Nations and Freedom MEPs: 58 Vote share: 7.7% EU elections 2019 Europewide results Europe of Freedom and Direct Democracy MEPs: 54 Vote share: 7.2% EU elections 2019 Europewide results European United Left–Nordic Green Left MEPs: 38 Vote share: 5.1% EU elections 2019 Europewide results Non-Inscrits and other parties Non Inscrits (MEPs not affiliated with a parliamentary grouping): 6 Vote share: 0.8% Other parties: 29 Vote share: 3.9%

The warning follows Boris Johnson’s threat to carry out a crash-out Brexit in the autumn in October, if necessary, which rival Tory candidates have quickly copied.

The chancellor dismissed their claims of trying to renegotiate a better deal before than as “a figleaf”, pointing out there would be no time, even if the EU was willing.

“The EU will not renegotiate the withdrawal agreement – I’m quite clear about that. They wouldn’t be able to because of their own political fragility,” he said.

Mr Hammond added: “In fact, the negotiation is a figleaf to do what is in fact a policy of leaving on no-deal terms.”

And he warned: “A prime minister who ignores parliament cannot expect to survive very long.”

The chancellor declined to say which of the eight candidates now running to be Tory leader he would back. Others are expected to join the race.

He said he wanted to hear their plans “to win a general election against Corbyn, their plans for the future”.

On a no-confidence vote, he warned it would be “a dangerous strategy” to be “boxed in with commitments you find it very difficult to deliver on”.

Asked again if he could vote against the government on such a motion, the Chancellor said: “It would challenge not just me, but many of our colleagues, and I hope we will never get to that position.”

Earlier, Mr Raab, warned MPs would be unable to stop him carrying out a crash-out Brexit if he wins the Tory leadership race, vowing to be “resolute”.

The former Brexit secretary ruled out a further Article 50 delay, vowing: “I will not ask for an extension.”