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.

Although French president Emmanuel Macron insisted that "nothing is settled", other leaders arriving at an emergency summit in Brussels indicated they were ready to back European Council president Donald Tusk's proposal of a long extension to Article 50 talks.

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.

But pressed over whether she stood by her comment in Parliament that "as Prime Minister" she would not delay Brexit beyond the end of June, she responded 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.

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.

May set out her case for a short extension in a presentation behind closed doors lasting around one hour, 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.

An apparently relaxed Prime Minister laughed and smiled with Angela Merkel as the German chancellor showed her pictures on her tablet depicting the pair wearing jackets of exactly the same shade of blue as they addressed their parliaments earlier in the day.

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".

Despite having face-to-face talks with the PM in Paris on Tuesday, the French President said he needed more "clarity" and was "impatient" to hear what Mrs May would say. "We must understand today why this request? What is the political project which justifies it and what are the clear proposals?" he said.

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 Withdrawal Agreement from passing through Parliament in time to leave on the scheduled date of March 29, 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."

Other leaders said that the main condition likely to be imposed in return for any extension was that Britain should prepare for European Parliament elections on May 23, though it need not actually vote if ratification is achieved earlier.

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."