The Democratic Unionist Party (DUP) has demanded an explanation from prime minister Theresa May after she warned that a no-deal Brexit could spark "changes to everyday life in Northern Ireland" that jeopardise the union.
Deputy leader Nigel Dodds said Mrs May needed to clarify what she meant when she spoke to factory workers in Stoke-on-Trent in Staffordshire on Monday, to avoid the suggestion that she was engaging in "foolish talk".
In her speech the prime minister sought to show how much better for the UK her withdrawal agreement was compared with a no-deal Brexit.
Just hours ahead of a meaningful vote on her withdrawal agreement, she said: "With no deal we would have: no implementation period, no security co-operation, no guarantees for UK citizens overseas, no certainty for businesses and workers here in Stoke and across the UK, and changes to everyday life in Northern Ireland that would put the future of our union at risk."
This provoked uproar from Mr Dodds, whose party has played down the risks of a no-deal Brexit.
The DUP believes the Irish border backstop would undermine the constitutional integrity of the UK and bring a united Ireland a step closer by creating barriers between Northern Ireland and Great Britain.
Both the EU and the British government have been at pains to say that no hard border would return between Ulster and Ireland, a move which would breach the Belfast Agreement.
Mr Dodds said: “The prime minister must explain this comment. What exactly would the government be changing?
“If this is nothing more than scaremongering, then the prime minister should cease from such foolish talk.
"Indeed, the Irish prime minister, Leo Varadkar, has said that the Republic of Ireland is not making preparations for a hard border even in the event of no deal being agreed." – Press Association