Theresa May is to address EU leaders as she battles to keep her faltering hopes of securing a Brexit deal alive.
The Prime Minister travels to Brussels for what had been billed as “the moment of truth” in the negotiations amid growing concerns the two sides will be unable to bridge the gap over the key issue of the Irish border.
The meeting is the occasion when the leaders of the remaining 27 member states were supposed to give the green light for a special summit in November to finalise the terms of Britain’s withdrawal.
But after hastily arranged talks between the EU’s chief negotiator Michel Barnier and Brexit Secretary Dominic Raab broke up on Sunday without agreement, the negotiations are once again deadlocked.
European Council president Donald Tusk has warned that without new “concrete proposals” from the British to break the logjam over the so-called Irish border “backstop”, further progress may be impossible.
However, with her party split - and some Tory MPs openly calling for her to go - Mrs May has little room to manoeuvre if she is to secure a deal which stands any chance of getting through Parliament.
Ahead of her visit to Brussels, Mrs May was able to secure the backing of her Cabinet - at least for now - amid reports that some Brexiteer ministers were prepared to quit if she gave too much ground to Brussels.
During a marathon three-hour meeting on Tuesday, she insisted she would not accept an agreement on the backstop - intended to maintain an open border between Northern Ireland and the Republic - which undermined the integrity of the UK or tied it indefinitely to EU customs arrangements.
However, there was anger among Tory Brexiteers after The Daily Telegraph reported that Chancellor Philip Hammond warned the meeting that the UK could still have to pay the EU up to £36 billion of the £39 billion “divorce bill” to settle its outstanding liabilities, in the event of a no-deal break.
Foreign Secretary Jeremy Hunt, meanwhile, said ministers needed to stand “four square” behind the Prime Minister and warned attacks by Brexiteers such as Boris Johnson risked derailing Brexit altogether.
“What I would say to Boris is be careful because there is a real danger that if all of us Conservative MPs do not stand behind the Prime Minister at a moment like this, the danger is that Brexit will be derailed altogether,” he told the Daily Mail.
“I am sure that this is the last thing Boris wants.”
The Prime Minister will briefly address the leaders of the EU 27 on Wednesday evening before they discuss the state of play in the Brexit negotiations over a working dinner while she leaves.
Her official spokesman said she would take the opportunity to set out the areas where progress had been achieved while stressing her commitment to finding an agreement.
“We want to secure a deal as quickly as possible. We think it is in the best interests of the UK and European Union to forge that deep future partnership,” the spokesman said.
With hopes of a November summit fading, focus has turned to the next scheduled meeting of the European Council in December as the last chance to secure a deal and get it ratified by the UK and European parliaments before Britain leaves in March 2019.
Mr Barnier told a meeting of EU 27 foreign ministers in Luxembourg that “more time” was needed to find an agreement to deliver an orderly UK withdrawal and resolve the Irish border issue.
“We will take this time, calmly and seriously, to find this global agreement in the next weeks,” he said.
Some Tory Brexiteers, however, believe the Prime Minister has deliberately pushed back the negotiations to the last possible moment to pressurise MPs into backing her plan rather than see the UK “crash out” without an agreement.