Theresa May's hopes of a Brexit breakthrough are hanging in the balance after the EU appeared to rebuff her latest appeal for help in getting her withdrawal deal through Parliament.
The EU's chief negotiator Michel Barnier said they would be "working intensively" in the coming days to resolve the impasse over the Northern Ireland backstop ahead of Tuesday's crunch vote by MPs.
However his suggestion the UK could unilaterally pull out of the planned single customs territory if it chose was dismissed by ministers as an attempt to "rerun old arguments".
With a very real deadline looming, now is not the time to rerun old arguments. The UK has put forward clear new proposals. We now need to agree a balanced solution that can work for both sides https://t.co/yN9ZuiVj1M
— Steve Barclay MP (@SteveBarclay) March 8, 2019
The DUP, which props up the Government at Westminster, said Northern Ireland would still be in the backstop, effectively drawing a "border in the Irish Sea" with the rest of the UK, something Mrs May has repeatedly ruled out.
There had been speculation the Prime Minister could fly out to Brussels early on Monday to clinch a deal if an agreement on the backstop – intended to prevent the return of a hard border on the island of Ireland – was within grasp.
Mrs May had been seeking legally binding assurances that the UK could not be tied indefinitely to the EU through the backstop in an attempt to win round MPs who inflicted a massive defeat on the Withdrawal Agreement in a previous vote in January.
But in a sign ministers are preparing to go back to the Commons on Tuesday without fresh concessions, Chancellor Philip Hammond said such fears about the backstop were overblown.
In an interview with the Financial Times, he urged Tory MPs to back the Withdrawal Agreement anyway, saying it would enable him to start spending the "insurance fund" built up in case of a no-deal break.
"There is nobody in the EU I've ever come across who thinks the UK could be held in perpetuity in an arrangement that was detrimental to its interests against its will. Who is going to enforce such an arrangement on this?" he said.
Mr Barnier's latest intervention came after Mrs May delivered a speech on Friday imploring EU leaders for "one last push" to help her get her deal over the line in the Commons.
It was unclear whether his comments, in a series of tweets, were intended as a new offer or simply a restatement of the EU's position after his talks on Tuesday with Attorney General Geoffrey Cox and Brexit Secretary Stephen Barclay failed to reach agreement.
He said the EU was committed "to give UK the option to exit the Single Customs Territory unilaterally, while the other elements of the backstop must be maintained to avoid a hard border".
The EU was also ready to give "legal force" to reassurances given to Mrs May concerning the operation of the backstop in January in a joint letter from European Council president Donald Tusk and European Commission president Jean-Claude Juncker.
Mr Barclay, however, suggested the latest proposals from Brussels were simply a return to an earlier version of the backstop which had already been rejected by the UK.
"With a very real deadline looming, now is not the time to rerun old arguments," he said.
"The UK has put forward clear new proposals. We now need to agree a balanced solution that can work for both sides."
DUP deputy leader Nigel Dodds said Mr Barnier's offer would annexe Northern Ireland from the rest of the UK- something Mrs May has repeatedly said that no British prime minister could agree to.
"This is neither a realistic nor sensible proposal from Michel Barnier. It disrespects the constitutional and economic integrity of the United Kingdom," he said.
"This is an attempt to get ahead of a possible blame game and appear positive when in reality it is going backwards to something rejected a year ago."