The EU has said it is now up to MPs to decide the next steps for Brexit and it remains “committed” to agreeing a deal in time for the UK to leave this month.
Officials said they had offered fresh assurances on the issue of the Irish backstop ahead of Tuesday’s second vote by MPs on Theresa May’s deal.
It was “now for the Commons to take an important set of decisions”, they said.
Labour and Tory MPs have told the PM she must honour her commitment to put her deal to the vote again on Tuesday.
Amid speculation the vote could be postponed or downgraded, No 10 confirmed it remained the plan to go ahead with another “meaningful vote”, with the motion to be debated to be published later on Monday.
Downing Street said the PM’s focus was “getting on with the work required to allow MPs to support the deal and to bring this stage of the process to an end”.
The BBC’s political editor Laura Kuenssberg said the prime minister was “likely” to head to Strasbourg later – where the European Parliament is based.
But a European Commission spokesperson would not confirm this, saying: “We keep talking and working.”
The spokesperson said that European Commission President Jean-Claude Juncker and Theresa May had spoken by phone on Monday.
The UK is due to leave the EU on 29 March but MPs rejected the withdrawal deal on offer in January and demanded major changes.
The government has been seeking changes to the Irish backstop, the safety net designed to maintain an open border on the island of Ireland, and only to be used as a last resort.
But the details of it were a sticking point for many MPs when they voted her deal down in January. They worry that – in its current form – the backstop may leave the UK tied to the EU indefinitely.
What is the EU saying?
In a statement, the Commission said it had put forward proposals to try and reassure MPs the backstop “if used will apply temporarily”.
While “no further meetings” at ministerial level were scheduled before Tuesday’s vote, a spokesman said both sides would remain in “close contact” and the EU was willing to meet UK negotiators at any time.
He added: “We are committed to using our best endeavours to find a subsequent agreement that replaces the backstop…We are committed to ratifying this deal before 29 March.”
Earlier, the EU’s chief Brexit negotiator, Michel Barnier, said that talks about the UK’s withdrawal from the bloc were now between the British government and MPs.
The BBC’s political editor Laura Kuenssberg said the chances of Parliament approving Mrs May’s deal appeared “very remote” at this stage.
She said it was still possible that the UK would come back with some new assurances from the EU over the backstop which could “get the numbers down” and limit the scale of any defeat.
MPs insist vote must take place
Mark Francois, a member of the European Research Group of Brexit-backing Tory MPs, said unless “something amazing” materialised, the outcome of Tuesday’s vote would be similar to that in January – when the government lost by a record 230 votes.
“In very simple terms if you ask the same question, you get pretty much the same answer,” he told BBC Breakfast.
Former Labour cabinet minister Yvette Cooper said Mrs May “had given me her word” to MPs that this week’s votes would happen.
“I don’t believe she would straight up lie on something as important as this,” she said.
Ms Cooper, who has spearheaded parliamentary efforts to rule out a no-deal exit, called for talks on the withdrawal deal and the UK’s exit to be put on hold while the PM tried to build a consensus in Parliament and the country on what kind of future relationship it wanted with the EU.
“The stakes are far too high to assume she has this under control,” she said. “If she won’t find a way forward, Parliament has a responsibility to do so instead.”
And Conservative MP Nick Boles tweeted that the prime minister had promised to hold a second meaningful vote by 12 March.
There will be an urgent question from Labour in the Commons later, asking Mrs May for an update on the progress made in achieving legal changes to the withdrawal agreement and the timetable for its approval.
Shadow Brexit secretary Sir Keir Starmer said it was “imperative” that Mrs May responded, rather than sending a junior minister.
“Accountability for the complete mess we are in lies with her,” he said.
Writing in the Daily Mail, pro-Brexit Environment Secretary Michael Gove said while the prime minister’s deal was a compromise, it should not be rejected “for that reason alone”.
But former cabinet minister Boris Johnson, who campaigned alongside Mr Gove to leave the EU, said there was “no way” he would vote for the backstop in its current form.
“The UK will have less sovereign power to withdraw from the backstop than it has to leave the EU itself,” he wrote in the Daily Telegraph. “It is quite a bewildering state of affairs.”
As things stand, the chances of Theresa May getting approval in the Commons tomorrow for her Brexit compromise, reversing a defeat of more than 200 votes, are very remote.
That said, it is quite possible to get those numbers down. Despite the fact the talks are stuttering with Brussels, it is still likely there will be some kind of piece of paper that emerges from the Berlaymont building – those edifices in Brussels where negotiators have been locked for the past few days.
There is likely to be some kind of reassurance on paper out of those talks, probably at some point later today.
The political point though is this: It is very unlikely – very unlikely – that it’s going to be enough to get the kind of revision to the deal that could comfortably reverse the defeat for the prime minister.
That’s why some MPs are starting to say, as they did last time, it is unwise for her to keep marching into gunfire to do again what no prime minister had done in recent memory – to go into a crucial vote all but knowing you are going to lose, and lose badly.
And that’s why things are so risky this week.
What could happen this week?
- Theresa May’s deal is expected to face a “meaningful vote” in Parliament on Tuesday
- If it’s rejected, a further vote has been promised for Wednesday on whether the UK should leave without a deal
- If that no-deal option is rejected, MPs could get a vote on Thursday on whether to request a delay to Brexit from the EU.