Ms Foster yesterday shot down a deal over the border, telling Theresa May she would no longer support her Government in a confidence and supply deal if the situation of Northern Ireland was any different to that of the UK.

She said she could have reiterated her position much earlier, but confirmed rumours she had been prevented from seeing the text of the deal.

She said: “We’d been in discussion with the Conservative Party right throughout and we’d asked for the text on a number of occasions, only to be told that there was no text at that particular occasion. 

“We spoke on Sunday evening, didn’t have text, and the text landed with us late on Monday morning.

“That left us in a very difficult position, we had to look at the text and try to understand what the ramifications of the text were.

“Once we had the time to do that, we realised that in no way could we sign up to that text, because essentially it was making a red line down the Irish Sea.”

As Ms Foster understands it, the Irish Government prevented the DUP from seeing the deal.

She said: “There have been reasons given to us as to why we weren’t given the text until so late on.

“One of those reasons is that the Irish Government wouldn’t allow them to share that text.”

Ms Foster also said she remains “unequivocal” to her opposition to a special Brexit deal for Northern Ireland, claiming it could break up the UK.

The DUP leader dug her heels in over the Ireland Brexit crisis after a deal on the Irish border was reached, then abandoned yesterday. 

She defiantly told Sky News: “In terms of our constitutional position, in terms of our economic position, there must be no borders between the constituent parts of the United Kingdom.”

She said she had made this clear to Theresa May when she was finally contacted with the details of a deal on the border at Monday lunch time.

The Prime Minister’s failed deal came after Irish Taoiseach Leo Varadkar said he was “unequivocal” that there could be no hard border on the island of Ireland after Brexit.

The deal was needed to move the Brexit talks onto the subject of trade after Mr Varadkar persuaded the entire EU to freeze Mrs May out until she agreed.

It would have effectively kept Northern Ireland in the single market and customs union after Britain leaves EU.

However Britain still stands to leave the single market and customs union - which Ms Foster believes would have separated Northern Ireland from the rest of the UK.

She said: “The Irish Prime Minister can be as unequivocal as he likes, I’m also unequivocal.

“This is no surprise to anyone, that I’m a unionist and I want to see the retention of the union or political reasons, but importantly for economic reasons as well. 

“Great Britain is our biggest market, 72 percent of our goods that leave Belfast port go to Great Britain. Why on earth would I cut off that market, just for a smaller market in the Republic of Ireland? 

“We want to see progress, we don’t want to see a hard border, we want to have good relations with our next-door neighbours in the Republic of Ireland.

“But we are not going to cut ourselves off from the rest of the United Kingdom.”