EU Brexit negotiator Michel Barnier rejects Theresa May's backstop plan

Michel Barnier has firmly rejected Theresa May's plan to avoid a hard border in Ireland if the UK leaves the European Union without a Brexit deal.

In yet another blow for the Prime Minister, the EU's chief Brexit negotiator said Brussels could not accept the Government's suggestion that the whole of the UK should stay closely aligned with Europe's customs rules.

He insisted that only Northern Ireland could do so - an idea which Mrs May has already dismissed as "unacceptable".

Mr Barnier also rejected the UK's desire to time-limit any "backstop" arrangement, insisting that it would have to stay in place until a solution is found to the Irish border issue.

Speaking at a press conference in Brussels, he said the six-page document presented by the UK yesterday "raises more questions than it provides answers".

He said the backstop proposals "cannot be extended to the whole UK - it has been designed for the specific situation of Northern Ireland".

Mr Barnier added: "We have provided this exceptional proposal on behalf of the EU to include Northern Ireland in our customs territory. That is quite an exceptional offer by the 27 (other member states) and there are no other comparable examples.

"On an exceptional basis, therefore, we have wanted to make our contribution to north/south co-operation in Ireland, the Good Friday Agreement and the need to avoid a hard border."

The British proposal said the Government "expects" the backstop to be in place until the end of 2021.

But Mr Barnier said: "The other point of disagreement is on the issue of how temporary the backstop would be. Backstop means backstop."

He added: "This has to be a backstop which provides a guarantee under all circumstances - unless and until we find a solution and that's why the time-limited terminology doesn't work for us."

In a letter to Tory MPs last night, Mrs May conceded that her proposals were "unpalatable", but insisted that they were better than the Brussels offer and probably would not be needed anyway.

Mr Barnier's outright rejection of her plan threatens a fresh crisis for the Prime Minister, who only narrowly managed to stop Brexit Secretary David Davis from resigning following tense talks yesterday.

Boris Johnson then caused another row by criticising Mrs May's handling of the Brexit negotiations and accusing the Treasury of being the "heart of Remain".

Labour MP Ian Murray, of the pro-EU People’s Vote campaign, said: "Theresa May’s flimsy Brexit proposal has lasted less than 24 hours. As predicted, her offer of half-baked fudge on the so-called ‘backstop’ option has been wholly rejected by the EU.

"The Government’s inability to negotiate sensibly and in the national interest is now a matter of profound concern for every business and individual who will be impacted by a bad Brexit deal.

"The irreparable divisions in the Cabinet mean the negotiations are now collapsing into what Boris Johnson has described as a ‘meltdown’."