The EU’s chief Brexit negotiator, Michel Barnier, has said it is difficult to see how the impasse over the Northern Ireland backstop can be overcome.

Mr Barnier said the EU “remains open to talks and progress”, but that the UK side had yet to come forward with proposals which could offer the basis of a solution.

“Based on current UK thinking, it is difficult to see how we can arrive at a legally operative solution which fulfils all the objectives of the backstop,” he said, following talks in Berlin with German foreign minister Heiko Maas.

Boris Johnson speaking to reporters on his flight to New York
Boris Johnson speaking to reporters on his flight to New York (Stefan Rousseau/PA)

His downbeat assessment came as Boris Johnson was preparing to meet key EU figures on the sidelines of the United Nations General Assembly in New York.

Mr Johnson has said that he wants Britain to leave the EU with a deal on October 31 – the current EU deadline – but is adamant that the backstop must be scrapped.

Speaking to reporters on the flight to the US, the Prime Minister insisted “a great deal of progress” had been made in the talks, although he sought to play down suggestions a breakthrough was imminent.

“There might be, but I don’t wish to elevate excessively the belief that there will be a New York breakthrough.

“We will be pushing ahead but there is still work to be done.”

He said it was “very encouraging” that European Commission president Jean-Claude Juncker had said he was not wedded to the mechanisms of the backstop – intended to ensure there was no return of a hard border with the Republic.

He said there was “interest” in his proposals for the island of Ireland to be treated as a single zone for agri-food purposes, but acknowledged there were “still gaps and still difficulties” which needed to be resolved.

“It would be still fair to say I’m in the same position I was. I think cautiously optimistic would be about right,” he said.

Speaking later in New York, Mr Johnson said he hoped the EU would see the move on agri-food products was a “helpful” concession on the British side.

Asked what he wanted to see from Brussels, he replied: “A broader understanding of quite how forward looking and forward leaning the UK has been with our suggestions.”

The Prime Minister is due to meet European Council president Donald Tusk on Monday, before talks with German Chancellor Angela Merkel and French President Emmanuel Macron.

He will then meet his Irish counterpart Leo Varadkar on Tuesday.

Irish foreign minister Simon Coveney has warned that a “wide gap” remains between the UK and the EU side on a new Brexit deal.