Theresa May could cling to power for as long as a year, as EU leaders looked set to offer the UK a lengthy delay to Brexit.
Most EU leaders at an emergency summit in Brussels appeared ready to back European Council president Donald Tusk’s proposal of a long extension to Article 50 talks.
But agreement was being held up by French President Emmanuel Macron, who insisted: “For me, nothing is settled, and in particular no long extension”.
Mrs May has asked for a delay to June 30, with a break clause allowing the UK to leave as soon as Parliament has ratified her Withdrawal Agreement.
She told MPs last month that “as Prime Minister” she would not delay Brexit beyond the end of June.
But arriving in Brussels, she played down the significance of the comment, insisting that the important issue was securing the flexibility to leave early and avoid having to take part in European elections in May.
Tory sources said that the PM stood by commitments made to the backbench 1922 Committee that she would hand over to a successor for the second phase of negotiations after ratification.
Mr Tusk’s proposals could postpone the opening of the next phase, dealing with the future UK/EU trade and security relationship, to the spring of 2020.
And agreement in Brussels would ease the pressure to force Brexit legislation through, allowing MPs to quit Westminster on Friday rather than give up a second week of their Easter break.
Mrs May set out her case for a short extension in a one-hour presentation behind closed doors, during which she answered questions from the leaders of the 27 other member states.
She then left the room to allow the EU27 to discuss the UK’s future in her absence over a dinner of scallop salad, loin of cod with brown shrimps and iced macadamia nut parfait.
An apparently relaxed Prime Minister laughed and smiled with Angela Merkel as the German chancellor showed her pictures on her tablet computer depicting the pair wearing jackets of exactly the same shade of blue as they addressed their parliaments earlier in the day.
Mrs Merkel told German MPs that the EU27 “may well” go for a longer delay, although the UK would be allowed to leave “very quickly” if Parliament approves a withdrawal deal.
But as he arrived in Brussels, Mr Macron insisted that “for me, nothing is settled, and in particular no long extension”.
And he was reported to have dug in his heels in the round-table discussion, insisting on a short extension and warning that no-deal Brexit would be better than allowing the UK to remain as a disruptive influence for months on end.
One diplomatic source was quoted as saying: “It will take hours before we pull him down from his tree.”
Mrs May said: “I have asked for an extension to June 30, but what is important is that any extension enables us to leave at the point at which we ratify the Withdrawal Agreement, so we can leave on May 22 and start to build our brighter future.”
In a swipe at the Brexit rebels who blocked her deal from passing through Parliament in time to leave on the scheduled date of March 29, Mrs May said: “I know many people are frustrated that the summit is taking place at all, because the UK should have left the EU by now.
“I greatly regret the fact that Parliament hasn’t been able to pass a deal that would have enabled us to leave in a smooth and orderly way.
“But I and the Government continue to work to find a way forward. We have been talking with the opposition. There’s been serious and constructive talks and they will continue tomorrow.”
Lithuanian President Dalia Grybauskaite rejected suggestions that countries like hers now held Britain’s fate in their hands.
“It is only up to the UK to decide,” she said. “Your country’s future is only in your hands, nobody else. It’s only up to you.
“You decide your fate, not us. We would only like to help you make this decision.”
Labour’s Jeremy Corbyn welcomed comments from Irish Taoiseach Leo Varadkar suggesting he is ready to contemplate a role for the UK in helping decide EU trade policies if it remains in a customs union after Brexit.
Mr Varadkar said that it would be in the UK’s interests to remain within the European trading bloc.
And he added: “It’s also in our interest to have the UK to be in our bloc and I think we would be generous in understanding that the UK couldn’t be a silent partner and would have to have a say in decisions being made.”
A customs union arrangement with a British say on trade deals is a central plank of Labour’s plan for Brexit.
Mr Corbyn responded with a tweet: “The Irish prime minister Leo Varadkar has confirmed this evening that Labour’s alternative plan for a new customs union with a UK say on future trade deals is credible and deliverable.”
The unanimous agreement of all 27 remaining EU states is needed to avoid a no-deal Brexit at 11pm on Friday, April 12.