British Prime Minister Theresa May will be told "emphatically" when she travels to Dublin this evening that the backstop must stay in place.
The embattled UK leader's tour of Europe will take her to Government Buildings where it is understood Taoiseach Leo Varadkar will stand firm against the notion that the Withdrawal Agreement can be amended.
Irish officials are now openly speculating that the most straightforward solution to the political crisis in the UK is to delay Brexit Day well beyond next March.
Ministers yesterday discussed contingency plans for a no-deal scenario, but the Government continues to refuse to release any substantial details.
Tanaiste Simon Coveney provided colleagues with a four-and-a-half page update on Ireland's preparedness for Brexit at Cabinet, but took the document back afterwards, fearing it would find its way into the public domain.
"They are afraid to tell people how bad it's going to be if there's no deal. The real hope is that something will happen," one minister admitted.
Sources said the document contained some details on plans for ramping up the recruitment of customs, veterinary and health officials.
It also noted that swathes of legislation would have to be amended by the Dail in a hurry to acknowledge that the UK is no longer inside Europe's single market and customs union.
Dublin will be looking to the EU to ensure workable arrangements are in place to allow air traffic to continue if the UK crashes out.
Ministers have been told to continue insisting that Ireland is not preparing for a hard border, even as the prospect of a no-deal grows.
Mrs May met with Dutch prime minister Mark Rutte in The Hague and German leader Angela Merkel in Berlin yesterday.
Both insisted negotiations on the Withdrawal Agreement could not be reopened, but that they were willing to give assurances about how the exit treaty would be interpreted.
Mrs May's mission then moved to Brussels where she held talks with EU Council President Donald Tusk.
"Long and frank discussion with PM Theresa May ahead of Brexit summit. Clear that EU 27 wants to help. The question is how," he tweeted afterwards.
That is what she will debate with Mr Varadkar in Dublin at around teatime today.
It is understood the Taois- each will offer her a "sympathetic ear" but will not cede ground on the operation of the backstop.
"Language is important, so maybe there is something that can be done outside of the Withdrawal Agreement, but it can't change the substance of the backstop," a source said.
While the two leaders will pose for a photographer on the steps of Government Buildings, it has been decided that they should not risk taking media questions together.
Mrs May is due back in the House of Commons for what is likely to be another round of theatrics before flying to Dublin.
There were conflicting reports last night about the level of support among Conservative MPs for a no-confidence motion.
Some Brexiteers in her party claimed that the threshold of 48 letters for a motion had been reached, but others indicated this was not the case.
Mrs May brushed aside speculation about her future, saying her focus was on "dealing with the issue".
"Whatever outcome we want, whatever relationship we want with the European Union in future, there is no deal available that doesn't have a backstop within it," she said.
"But we don't want the backstop to be used and if it is we want to be certain it is only temporary.
"It is those assurances that I will be seeking from fellow leaders over the coming days."
In the Dail, Mr Varadkar said everyone "wants to avoid a no-deal scenario, including in Britain, Ireland and the European Union".
He said the "power exists" for the UK "to remove the threat of no deal from its own people, its economy, from ours and from Europe, should it wish to do so".