Ireland warns UK over post-Brexit border issue
The UK government has been told by Ireland to "stand by its commitments" on avoiding a hard border between Northern Ireland and the Republic, BBC informed.
Irish prime minister Leo Varadkar said an arrangement with a time limit would not be "worth the paper it's written on".
The border issue is the main barrier to progress between the two sides.
With time running out, Theresa May, who briefs her cabinet on Tuesday, has to get both the EU and her MPs on side
The UK is due to leave the EU in March, and although 95% of the deal is said to be complete, the tricky bit is proving to be how to honour the commitment by both sides to guarantee no new hard border in Ireland.
It is an issue because after Brexit it will become the UK's land border with the rest of the EU, which has a single market and customs union so products do not need to be checked when they pass between member states.
There have been warnings that a hard border would undermine the peace process in Northern Ireland.
But unless negotiators can make decisive progress on how to guarantee no new visible checks, a special summit to finalise the UK's withdrawal will not take place.
There is disagreement on whether the "backstop" they have agreed to put in place should apply to Northern Ireland, or the whole of the UK - and on whether it can be time-limited or revoked by the UK.
Tory Brexiteers are concerned the UK could end up locked in a customs union with the EU without a fixed end point.
Writing in The Sun, former foreign secretary Boris Johnson said this would be an "absolute stinker" of a deal and warned of a "surrender to Brussels" with the UK staying tied to EU rules in years to come.
Mrs May has insisted that any arrangement would be "strictly time limited".
This, however, is not the view of the EU.
On Twitter, Irish Foreign Minister Simon Coveney said a time-limited arrangement - or one that could be unilaterally ended by the UK - would never get EU backing.
"Still necessary to repeat this, it seems," added the EU's deputy chief negotiator, Sabine Weyand.
And Mr Varadkar said the UK had agreed to a legally-binding "backstop" to apply "unless and until" it is superseded by a new agreement.
"I think it's reasonable for us to expect a country like the United Kingdom and a government like the UK government to stand by its commitments," he said.
Mr Varadkar described the UK as a "divided kingdom" over Brexit, saying this made it "very difficult to come to an agreement".
While the EU has objected to a time-limited UK-wide arrangement, its suggestion of a backstop that is specific to Northern Ireland has been ruled out by Mrs May who says it would undermine the integrity of the UK by creating a new border down the Irish Sea.
The prime minister says she does not think a "backstop" arrangement will be necessary as she wants to solve the border problem through the UK's long-term trade relationship with the EU, which has yet to be agreed.
Mrs May spoke to Mr Varadkar by phone on Monday morning "to take stock of the progress being made", Downing Street said, adding that: "In order to ensure that the backstop, if ever needed, would be temporary, the prime minister said that there would need to be a mechanism through which the backstop could be brought to an end."
The Irish government said Mrs May had "raised the possibility of a review mechanism for the backstop", and that Mr Varadkar had "indicated an openness to consider proposals for a review, provided that it was clear that the outcome of any such review could not involve a unilateral decision to end the backstop".