The EU’s chief negotiator Michel Barnier has said he is ready to come forward with an “improved” proposal on the Irish border in an attempt break the deadlock in the Brexit talks.

After briefing EU foreign ministers in Brussels, he insisted the EU offer would fully respect the “territorial integrity” of the UK.

He said the next full summit of EU leaders on October 18, would be the “moment of truth” when it would become clear whether it was possible for the two sides to reach a deal.

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

The issue of the border between Northern Ireland and the Republic has emerged as the main obstacle to an agreement ahead of the UK’s withdrawal in March 2019.

The EU is insisting on a “backstop” proposal which would see Northern Ireland remain in the customs union in the event of the two sides failing to reach an agreement in order to avoid the return of a “hard border”.

However Mrs May has rejected the plan as unacceptable arguing that it would effectively create a border in the Irish Sea between Northern Ireland and the rest of the UK.

Mr Barnier said he was working on a plan to “de-dramatise” the controls that would be necessary in the event of the backstop coming into play.

Brexit
The border between Londonderry and Donegal at Bridgend (Deborah McAleese/PA)

“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.”

He reminded the British, however, that the checks were the result of their decision to leave not only the EU but also the single market and the customs union.

“What we need in the 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.

His comments came as EU leaders prepare to gather in Salzburg on Wednesday for an informal summit – the first time they have met together since Mrs May published her Chequers blueprint for Brexit in July.

Brexit
Brexit Secretary Dominic Raab has urged the EU to make compromises (Peter Nicholls/PA)

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

Ahead of the meeting, Brexit Secretary Dominic Raab said it was time for the “compromises” made by the UK to be “matched on the EU side”.

In an interview with European newspapers, he said that there had to be movement on the Irish border issue.

“What I’m not going to do is to say that I would refuse to entertain any further proposals that the EU comes up with but they’ve got to be respecting the equities that we’ve set out,” he said.

While Mr Barnier highlighted the October summit as the “moment of truth”, European Council president Donald Tusk confirmed that a further summit could be held in November to finalise an agreement.

In a letter to EU leaders ahead of the Salzburg meeting, he said he wanted to avoid the “catastrophe” of a no-deal Brexit.

He said the meeting should also reconfirm the need for a “legally operational backstop” on Ireland to avoid a hard border.

Mr Tusk, who will chair the talks, also urged the leaders to work on “limiting the damage” caused by the UK’s withdrawal.

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