Ahead of the EU leaders’ summit in Salzburg, diplomats have warned Mrs May will need to make a substantial shift on her red lines in order to obtain a final Brexit deal, with the Irish border remaining a huge hurdle.
One senior diplomat said: “A lot of movement is needed by the UK side before we can actually reach an agreement.
“We need a substantial change in the UK red lines still.”
While a second EU diplomat added: “It seems that the UK needs to have a ‘darkest hour’ moment before they will shift position.
“But they will have to shift their position.”
The bloc is adamant it will not soften its stance on the UK signing up to a Northern Ireland ‘backstop’ solution.
There is yet to be further negotiations on Northern Ireland remaining in the customs union and single market in order to avoid a hard border in the event no deal is struck between the UK and the EU.
The Irish cabinet is expected to discuss a contingency plan for border controls between Britain and Ireland in the event of a ‘no deal’ Brexit at a meeting on Tuesday.
Tánaiste Simon Coveney warned the UK that time was running out.
He said: “I will be making very clear our continued strong support for Michel Barnier, welcoming his approach on efforts to de-dramatise the backstop aimed at agreeing the text of the protocol on Ireland and Northern Ireland.
“Time is short and it is important that the UK delivers on its commitments and engages constructively with the EU’s proposed backstop.
“The EU has been clear that without an agreement on a backstop, there cannot be an agreement on the withdrawal agreement.”
The bitter bloc also said the Chequers proposal on a common rulebook and customs deal did not respect the EU.
Another diplomat told The Guardian: “If you look at the Chequers proposals which have some elements in it that we support – external security, internal security – these are fine.
“Chequers had some other aspects that are more difficult.
“So the technical customs arrangement they proposed I think is too difficult to put into practice.
“There is work necessary to find language to express in this political agreement on the future relationship which meets up the four freedoms of the internal market and at the same time satisfies the position of the UK, and that of course plays into the backstop discussion on Northern Ireland.”
They added: “We don’t quite see the point in the red line in having their own trade agreements that is different to what we have in place.”