DUP leader Arlene Foster has told Sky News her party is unable to support Theresa May's Brexit deal while it "poses a threat to the integrity of the UK".

Ms Foster paid tribute to Mrs May and her team for engaging with the DUP during negotiations.

But she said there were still too many problems to allow her party to support the deal.

In a statement, the DUP said they had had "good discussions" with the government and that "some progress" had been made on domestic legislation.

They said all concerned "recognise the need to ensure that as we leave the European Union the economic and constitutional integrity of the United Kingdom is maintained".


But they added that the deal cannot be supported because there have not been "necessary changes" to the backstop.

The backstop refers to the customs plan to avoid a "hard" border between Ireland and Northern Ireland if a Brexit deal is not reached.

Image: Theresa May had met with the DUP but it's not been enough for the party

The statement adds: "The backstop if operational has the potential to create an internal trade border within the United Kingdom and would cut us off from our main internal market, being Great Britain."

Ms Foster told Sky News: "There is a difference between having an international treaty with a backstop that will become operative and a domestic legislation.

"The treaty will always come first.

"And that is our fundamental problem. It means the internal market has barriers between it between Northern Ireland and the rest of the UK. Constitutionally and economically, that will impact Northern Ireland."

She said she did not believe the choice was between Theresa May's agreement or no deal, and said there were plenty of conversations within the House of Commons to find another solution.

She said: "It has been made clear that parliament is not in favour of no deal.

"But we can't be in favour of something that threatens the union. The union comes first.

"In December 2017, we warned about the dangers of the backstop. The prime minister made a call and went ahead and then in November, the Withdrawal Agreement came. We warned her, but she went ahead.

"We can't sign up to something that would damage the union."

She reiterated the party's commitment to Brexit, and said she wished there was more time to discuss the opportunities available post-Brexit, but they had become "bogged down" in discussing the backstop.

Ms Foster said the DUP "regrets" not being able to support Mrs May's deal, adding she wanted an agreement that worked for the whole of the UK and Northern Ireland.

Ms Foster said her priority was the preservation of the union.

Asked if the DUP would abstain rather than vote against, Nigel Dodds, the DUP leader in Westminster, tweeted: "The DUP do not abstain on the union."