Theresa May is facing a high-pressure race against time to make progress in the Brexit talks amid a deadlock over the Irish border which threatens to drag on until the new year.
The Prime Minister is hoping to make a new offer by Friday (December 8) to satisfy both the Irish parties and Ulter's DUP, after the latter torpedoed her initial border proposal on Monday (December 4).
May is due to meet EU leaders at the European Council summit on December 14, and she is under pressure to push through a solution to the border issue by then. It is hoped that, if a solution is brokered by the time the EU bosses sit down together, they will declare that the Brexit negotiations can progress to the crucial trade stage.
However business chiefs are warning that, if there is any further delay, UK companies will activate contingency plans which will cost Britain jobs.
After talks in Dublin, Irish Taoiseach Leo Varadkar and Dutch PM Mark Rutte made clear the EU would not compromise and allow the Irish border to be kicked down the road to phase two of the talks, even if that means Britain crashing out with no deal.
On Wednesday (December 6) after a phone call with May, Varadkar said the Prime Minister was hoping to return with a new formal written offer "tonight and tomorrow," but warned if there was no agreement talks would be picked up in the New Year.
Downing Street said May told Varadkar she was "working hard to find a specific solution to the unique circumstances in Northern Ireland" and was committed to "moving together to achieve a positive result on this".
The Prime Minister also spoke with DUP leader Arlene Foster, whose rejection of plans for "regulatory alignment" between Northern Ireland and the Republic led to the collapse of the proposed deal on Monday.
But it is understood Foster has no immediate plans to fly to London for talks with May and any such move would depend on progress in negotiations between the DUP and the Government in London.
Meanwhile, 19 Remain-backing Tory MPs have written to May to condemn "highly irresponsible" pro-Brexit colleagues who "seek to dictate terms" that could leave Britain leaving the EU with no deal as negotiating pressure mounts.
Among the signatories to the letter were former cabinet ministers Nicky Morgan, Dominic Grieve and Stephen Crabb, as well as select committee chairs Sarah Wollaston and Bob Neill.