'Comes a point when you have to say enough is enough'
The DUP's Westminster leader Nigel Dodds has threatened to frustrate Theresa May's minority government should any Brexit deal "break up or fracture" the union.
However, the North Belfast MP said they would not go as far to pull the government down.
He was speaking to the BBC's Newsnight after the Prime Minister gave an update in parliament on the progress of the Brexit talks. She is pushing for a deal which would see the whole of the UK in a customs union with the EU in the event of a no-deal and for a time limited period.
However, the EU has said that option as a backstop must be in addition to the original backstop which would see Northern Ireland only remain in the customs union and with no time limit attached.
Nigel Dodds MP has warned the DUP would paralyse the Conservative’s domestic agenda but stop short of causing a general election if Theresa May breaks her word on Northern Ireland#newsnight | @NigelDoddsDUP | @nicholaswatt pic.twitter.com/hXQ1vaShzn— BBC Newsnight (@BBCNewsnight) October 15, 2018
Dodds said there were "very encouraging noises" from the Prime Minister's statement in the Commons.
However, he said in some of her answers she seemed not to be as clear "causing again some confusion".
"We need to see exactly what it is Theresa May is going to put forward," he said.
"We would certainly not want to pull the plug on the government and allow Jeremy Corbyn to get into Number 10.
"But under the fixed term parliament act there is a lot we can not support in terms of the government's domestic, financial, welfare and other legislation which does not trigger Jeremy Corbyn getting into Number 10.
"So what I would say to colleagues is, we do not want this. We want to work with the Conservative and Unionist party."
The DUP has a confidence and supply deal with the Tories which see its 10 MPs support the government on crucial legislation.
On Monday evening a group of Cabinet ministers met to discuss the developments, with Foreign Secretary Jeremy Hunt, Brexit Secretary Dominic Raab and Environment Secretary Michael Gove among those who attended.
Mr Dodds added: "If there was a suggestion the union, 'our precious union' as the Prime Minister described it be broken up or fractured in any way by the Conservative party, then clearly we would have to say 'how can we continue to implement your domestic agenda, your budgets and everything else?'.
"Of course we wouldn't push for a general election but there comes a point when you have to say 'enough is enough'."
Sinn Féin's Brexit negotiator Conor Murphy says the Irish border issue is “not a problem that we created for ourselves. We need a backstop arrangement which recognises the uniqueness of our position”.@conormurphysf | @MarkUrban01 | #newsnight pic.twitter.com/qgu3eS9q2F— BBC Newsnight (@BBCNewsnight) October 15, 2018
Sinn Fein Brexit spokesman Conor Murphy said his party got no further clarity from the Prime Minister after their meeting with her on Monday evening.
"It is the British border in Ireland and it is not a problem we created and we didn't create the problem of Brexit," he said.
"The British Prime Minister and the EU 27 in December recognised the uniqueness of the Irish situation, the border issues, the Good Friday Agreement and the implications for it as a consequence of taking us out of Europe against our will.
"The realty is we need a backstop arrangement which recognises the uniqueness of our situation. We can't have it time-limited. Brexit is not a one-off event.
"It has huge implications for those that live in my country.. and we want to ensure our rights and entitlement's are protected in those arrangements."
He said he wanted Brexit to "go well" when asked if a "disorderly" withdrawal would progress Sinn Fein's goal of securing a border poll.
He said he did not want to see peace threatened or the economy destroyed, "which is a real possibility of the consequence of Brexit".
"I think the view in Ireland is changing anyway, I think there is an inevitable drift towards an examination of the constitutional position in Ireland," he added.
"We don't want to see Brexit as a steam train to be driven through our political project on the island which is about reconciliation, about changing the politics of the island and that is why we have been so vociferous in terms of trying to get terms on a particular set of arangements."