Theresa May is heading to Brussels for an EU summit, less than 24 hours after surviving a vote of confidence.
The prime minister is seeking legally binding pledges from EU leaders on the Irish backstop – a key obstacle for MPs who oppose her Brexit deal.
The EU will not renegotiate the deal but may be willing to give greater assurances on the temporary nature of the backstop, the BBC understands.
The PM won the ballot on her leadership by 200 votes to 117 on Wednesday night.
The secret ballot was triggered by 48 of her MPs angry at her Brexit policy, which they say betrays the 2016 referendum result.
Speaking in Downing Street after the vote, Mrs May vowed to deliver the Brexit “people voted for” but said she had listened to the concerns of MPs who voted against her.
“I have heard what the House of Commons said about the Northern Ireland backstop and, when I go to the European council tomorrow, I will be seeking legal and political assurances that will assuage the concerns that members of parliament have on that issue,” she said.
At Thursday’s summit, she will have an opportunity to spell out face to face the problems surrounding the withdrawal agreement at Westminster to the 27 other EU leaders.
Without Mrs May, the EU leaders will then consider what could be done.
A draft of the European Council conclusions on Brexit says the EU would use its “best endeavours to negotiate and conclude expeditiously a subsequent agreement that would replace the backstop so that it would only be in place for a short period and only as long as strictly necessary.”
In other words, the EU would continue trying to negotiate a trade deal with the UK even if the Irish backstop had been triggered at the end of the transition period.
The Brexit withdrawal agreement only talks about ‘best endeavours’ being used to reach an agreement during the transition period.
But the draft put forward by the European Council could be subject to change, the BBC’s Adam Fleming says.
Westminster critics of Mrs May’s Brexit deal might also complain that it is not legally binding.
But the same document reiterates that the withdrawal agreement is not open to renegotiation, adding that it would not have been even if the Conservative Party had changed leaders.
The prime minister won the confidence vote with a majority of 83 – 63% of Conservative MPs backing her and 37% voting against her.
Mrs May spoke of a “renewed mission – delivering the Brexit people voted for, bringing the country back together and building a country that really works for everyone.”
Her supporters urged the party to move on but critics said losing the support of a third of MPs was “devastating.”
The BBC’s Laura Kuenssberg said the level of opposition was “not at all comfortable” for the prime minister and a “real blow” to her authority.
The outcome of the vote was welcomed by Austrian chancellor Sebastian Kurz, who said avoiding a no-deal exit from the EU was a “shared goal.”
But Mrs May still faces a battle to get her Brexit deal through the UK parliament, with all opposition parties and dozens of her own MPs against it.
Jacob Rees-Mogg, who led calls for the confidence vote, said losing the support of a third of her MPs was a “terrible result for the prime minister” and he urged her to resign.
Brexit-backing Tory MP Mark Francois told the BBC it was “devastating” that more than half of backbenchers not serving in the government had abandoned the prime minister.
“In the cold light of day when people reflect on that number – 117 – it’s a massive number, far more than anyone was predicting. I think that will be very sobering for the prime minister. I think she needs to think very carefully about what she does now.”