The DUP has demanded Theresa May comes clean about a reported plan to create a regulatory border in the Irish Sea to unlock Brexit negotiations.

Speaking to Sky News, the Northern Ireland party's leader, Arlene Foster, warned such a move would be an economic "disaster" and damage the UK's "constitutional integrity".

She claimed that the prime minister's silence had created a "vacuum" and called on her to publish any new plans to clear up any ambiguity.

It comes as the DUP's Brexit spokesperson, Sammy Wilson, warned: "We're not bluffing."

Mrs May's confidence and supply partners are needed to ensure she can pass new laws - including ones on Brexit - in the House of Commons.


On Monday, ex-Brexit minister Steve Baker told Sky News that if true, the proposal would probably see the DUP "bring down the government".

Bloomberg reported earlier that the UK was preparing a big pitch to Brussels on the backstop deal.

Mrs May was said to be ready to offer regulatory alignment between Northern Ireland and the Republic.

That would help maintain a frictionless border between the two countries, but create new regulatory checks on some products crossing the Irish Sea to mainland Britain.

The idea of creating a single market border within the UK has previously been derided by Mrs May, who said it was "something I will never accept and I believe no British prime minister could ever accept".

Mrs Foster responded by saying there had been "a lot of talk about this issue" but that she "wanted to see the text".

"What does it mean? What's been talked about?" she told Sky News.

"You can't talk in a vacuum - you actually need to see the text.

"If the government is putting forward text then let us see the text so that we can make our own assessment as to whether it creates a border down the Irish Sea.

"Because the prime minister is fully aware that that is a red line for us, because we value the constitutional integrity of the whole of the UK.

"And economically for Northern Ireland it would be a disaster."