Threat to UK government after DUP rejects UK-Dublin 'deal' on Irish border

Theresa May and Arlene Foster - Dominic Lipinski/PA Wire

DUP leader Arlene Foster has delivered a huge blow to Theresa May by rejecting a deal which would see the Republic and Northern Ireland maintaining the same trade rules after Brexit.

According to Irish state broadcaster RTE, the UK will agree to "continued regulatory alignment" between the two countries in order to clinch a deal in Brussels today.

That could effectively see Northern Ireland remain the European single market and customs union while the rest of the UK quits.

In a dramatic statement, Foster - whose 10 MPs prop up May's minority government - flatly rejected any concessions to Dublin by the UK government.

"We will not accept any form of regulatory divergence which separates Northern Ireland economically or politically from the rest of the UK,” she said.

"The economic and constitutional integrity of the United Kingdom must not be compromised in any way."

She added: “The Republic of Ireland for their part came to be guarantors of the Belfast agreement.

“They are clearly seeking to unilaterally change that Belfast agreement without our input or our consent and of course we will not stand for that.”

Irish prime minister Leo Varadkar has demanded written guarantees there will be no hardening of the 310-mile border between the Republic and Northern Ireland after Brexit.

Another option would be the whole of the UK staying in the single market and customs union - which Mrs May has categorically ruled out, and which would not be accepted by the likes of Boris Johnson and Michael Gove.

Meanwhile, former First Minister of Northern Ireland David Trimble today said leaving the province in some EU institutions unlike the UK would be "a thoroughly bad idea”.

"If it operates on a purely Northern Ireland basis it's going to put Northern Ireland businesses potentially at a very significant disadvantage," the ex-UUP boss and now Tory peer said.

“Because they would be locked into European regulatory provisions whereas the rest of the UK - which is their major market - is free from those and may have a different regulatory provisions entirely."

May was hoping to secure enough agreement on the Irish border - as well as the Brexit divorce bill and citizens' rights - at a lunch with European Commission president Jean-Claude Juncker and EU chief negotiator Michel Barnier to allow the negotiations to move onto trade in the New year.

She is then due to meet with European Council president Donald Tusk, who earlier today seemed optimistic of an agreement.

"Tell me why I like Mondays!" he tweeted. "Encouraged after my phone call with the Taoiseach on progress on Brexit issue of Ireland. Getting closer to sufficient progress at December #EUCO."