Northern Ireland’s political parties remain sharply divided over Brexit ahead of a possible Westminster vote.
The largest party, the DUP, described a High Court ruling that said Parliament must vote before the UK government can trigger Article 50 to leave the EU as “disappointing”.
But, DUP leader Arlene Foster said Brexit would still happen.
Sinn Féin’s Martin McGuinness said he has “no faith” that MPs will respect Northern Ireland’s referendum result.
Overall, the UK electorate voted to leave the EU, but in Northern Ireland, a majority of people (56%), voted to stay.
Thursday’s High Court ruling was a defeat for the Westminster government, but it will now appeal the decision at the Supreme Court.
The SDLP’s Mark Durkan said his party’s three MPs would “unapologetically defend the will of the 56% of people who voted to remain in the European Union”.
The Ulster Unionist Party (UUP), which has two seats in the House of Commons, said its MPs would vote in support of the UK-wide result.
With eight seats, the DUP is the joint-fourth largest party in the Commons and is strongly in favour of leaving the EU.
“On 23 June, the British people as a whole gave a clear mandate for the UK government to leave the EU,” DUP MP Nigel Dodds said.
“There must be no attempt to block Brexit by people who refuse to accept the will of the people of the UK.”
His party leader Arlene Foster has said the ruling will not stop Brexit from happening.
She said it was “clear” that the UK government was going in a direction that represented the views of the majority of people who voted for the UK to leave the EU.
Sinn Féin has four MPs but the party does not take its seats in the House of Commons under a long-held policy of abstentionism.
At a Stormont press conference, Northern Ireland’s Deputy First Minister Martin McGuinness was asked if his party would change its policy if there was a “crucial vote” on Brexit.
He replied that he had already seen a statement from the Labour Party which said it intended to respect the outcome of the UK’s Brexit referendum result.
Labour has 231 seats in the House of Commons, meaning it would be unlikely that Sinn Féin’s four MPs could have much influence on the vote.
However, Mr McGuinness said any decision to leave the EU would affect the whole island of Ireland.
“Brexit will have a massive impact on every one of Ireland’s 32 counties,” he said.
“So we believe that any decisions that need to be taken about the future of this island [should] be taken between our administration in the north and the government in Dublin.”
He added: “As far as I’m concerned, the assembly and the Dáil [Irish parliament] are the people who make the decisions about the future of the people who live in this island.”
However, Taoiseach [Irish Prime Minister} Enda Kenny said the decision of the High Court in London was a matter for the British government.
Sinn Féin President Gerry Adams said the Irish government needed to find alternatives to Brexit, and called on all interested parties to work to ensure Northern Ireland is given special status.
“The European Union can be quite flexible about making those types of arrangements, and the Irish government needs to be pursuing that position,” added Mr Adams.
Sinn Féin’s nationalist rivals, the SDLP, do take their seats at Westminster and the party welcomed the High Court ruling.
Mr Durkan said: “I have consistently called on the government not to begin the formal process of triggering Article 50 on withdrawal from the EU until its proposals have been fully considered in the House of Commons and voted upon by MPs.”
He claimed it was now “incumbent on other MPs from Northern Ireland to commit to representing the democratically stated will of people here”.
The UUP’s statement said: “Parliament voted to give the people of the United Kingdom the opportunity to vote in a straight in/out referendum.
“On the 23rd June the people of the United Kingdom voted to leave the European Union and on that basis, should the appeal be unsuccessful, our MPs will vote to trigger Article 50.”
The Alliance party does not have any MPs but its Brexit spokesperson Stephen Farry also welcomed the ruling.
“This at least now provides an opportunity for Parliamentary and Assembly scrutiny of the issues around Brexit,” he said.
Mr Farry added that the UK government needs “to spell out much more clearly what they intend Brexit to mean”.
Brexit: NI parties remain divided ahead of a potential vote in UK Parliament}