Boris Johnson has refused to rule out clinging onto power in order to force a no-deal Brexit if he loses a no confidence vote.
Asked on Thursday morning whether he would ignore MPs if they voted against him when parliament returns in September, the prime minister avoided the question.
“I think that MPs should get on what they have promised over and over and over again to the people of this country,” he said.
“They will deliver on the mandate of 2016 and leave the EU on 31 October.”
Johnson added: “We are going to leave the EU on 31 October, which is what the people of this country voted for.”
Jeremy Corbyn could call a vote of no confidence in Johnson’s government when parliament returns in the first week of September.
But it has been reported Johnson might refuse to resign as PM even if he lost.
Under the terms of the Fixed Term Parliaments Act, there would be a 14 day period after the vote for MPs to cobble together an alternative government.
If no alternative government could be formed a general election would be triggered.
But if Johnson refused to resign he could delay the election until after the October 31 Brexit deadline, forcing no-deal.
Even if a no confidence vote is held as soon as parliament returns from the summer break, the earliest a general election could be held is October 25 - less than a week before exit day.
The row has raised fears the UK is heading towards a constitutional crisis.
Robert Hazell, professor of government and constitution at University College London, said if MPs had “clearly indicated support” for an new PM, then Johnson would be expected to quit and recommend to the Queen she appoint his replacement.
“If he refused to do so, the Queen would be entitled to dismiss him and appoint the alternative as prime minister,” he added.
John McDonnell, the shadow chancellor, told the Edinburgh Fringe last night that Labour did not want to “drag the Queen into this” but might have no choice. “I would be sending Jeremy Corbyn in a cab to Buckingham Palace to say we’re taking over,” he said.