Theresa May is to issue a fresh call to EU leaders for compromise in the Brexit talks as Brussels’ chief negotiator said he was ready to come forward with a new offer on the Irish border.

As EU leaders prepared to gather in Salzburg, Michel Barnier said he was working on an “improved” plan to avoid the return of a hard border while respecting the territorial integrity of the UK in an attempt to break the talks deadlock.

After briefing EU foreign ministers in Brussels on Tuesday, Mr Barnier warned time for an agreement was running out and that the “moment of truth” would come at the next full EU summit on October 18.

“It is then we shall see whether agreement we are hoping for is in our grasp,” he told a news conference.

Brexit
Michel Barnier has said he is ready to make an improved offer on the Irish border (Niall Carson/PA)

The informal gathering of EU leaders in Salzburg will be the first time they have met together since Mrs May published her Chequers blueprint for Brexit in July.

The Prime Minister is expected to brief the other 27 leaders on proposals over dinner on Wednesday and they will then have a separate discussion on Thursday after she has left.

In an interview with the Daily Express she said it was the “right plan” for the UK while representing a “good deal for the EU”.

“I’m not going to be pushed away from doing what is necessary to get the right deal for Britain,” she said.

A senior No 10 source said she would tell them the UK’s position had “evolved” and that the EU would need to do the same if they were to get an agreement.

And she will make clear that the existing EU “backstop” proposal to avoid the return of a hard border between Northern Ireland and the Republic in the event of a no-deal Brexit remains “unacceptable”.

The Government argues Brussels’ plan, which would see Northern Ireland remain in the customs union until a new arrangement could be agreed, would effectively create a border between the North and rest of the UK.

Writing in German newspaper Die Welt, Mrs May said the UK and EU were close to agreement on withdrawal, but added: “Neither side can demand something completely unacceptable from the other.”

Mr Barnier said that his latest proposal to break the deadlock would “de-dramatise” the controls that would be necessary in the event of the backstop coming into play.

“We are ready to improve this proposal. Work on the EU side is ongoing.

“We are clarifying which goods arriving in Northern Ireland from the rest of the UK would need to be checked and where, when and by whom these checks could be performed,” he said.

“We can also clarify that most checks can take place away from the border at the company premises or in the markets.

“We need to de-dramatise the checks that are needed.”

There was no immediate response to his comments from either Downing Street or the Department for Exiting the EU, and it was unclear whether they would be sufficient to unlock the negotiations.

A No 10 source said Mrs May will tell the other leaders in Salzburg that a “disorderly” Brexit can still be avoided with “good will and determination” on both sides.

While she will say the UK will honour its commitment to ensure there is a “legally operative protocol” on the Irish border, it must preserve the constitutional and economic integrity of the UK, which the existing proposal does not.

In his comments, Mr Barnier reminded the British that the whole issue of the border had arisen as a result of their decision to leave not only the EU but also the single market and the customs union.

“What we need in withdrawal agreement is a legally operational backstop which fulls respects the territorial integrity of the UK. It is a backstop that will only apply unless a better solution is found,” he said.

Mr Barnier also made clear that time to reach a deal was running out with his comment that the October summit would be the “moment of truth”.

Attention had been increasingly focused on the prospect of a special summit in November to finalise an agreement, however Mr Barnier said it should be clear before then whether a deal was actually possible.

European Council president Donald Tusk said EU leaders should discuss arrangements for the “final phase” of the Brexit talks “including the possibility of calling another European Council in November”.

In a letter to leaders ahead of the Salzburg meeting he called on them to work on “limiting the damage” caused by Brexit.

“Unfortunately, a no-deal scenario is still quite possible. But if we all act responsibly, we can avoid a catastrophe,” he said.

Housing Secretary James Brokenshire said he remains “positive and confident” based on feedback from EU member states about how the Brexit process can be taken forward.

He told BBC Radio 4’s Today programme: “We have clearly evolved our position and it is now for the EU to evolve its position.

“I think the Chequers deal sets out a deliverable, workable plan.”

Pushed on whether the UK position could change, Mr Brokenshire replied: “We obviously want the EU to evolve its stance and we wait to see how they respond to this.”