SDLP Leader Colum Eastwood has called on Sinn Fein to take their seats at Westminster to vote against Article 50 being triggered.
Mr Eastwood was speaking following the Supreme Court ruling which rejected the government’s challenge to an earlier ruling that leaving the European Union will have to be put before parliament.
Mr Eastwood vowed that his party would be making their voice heard during the debates and talks at Westminster in the coming weeks.
He said: “This judgement marks a significant and serious departure from our devolution settlement. It significantly undermines the value placed on the democratic mandate of our Assembly.
“Northern Ireland voted to remain in the European Union, yet the Northern Ireland Assembly is being denied any role or rights in the upcoming negotiations with the European Union.
“The SDLP is now the only party standing by the will of the majority of people in Northern Ireland at Westminster. We will be the only voice of the 56% who voted remain.”
He added: “Although the Supreme Court disagreed with the view that there is a legal requirement to gain legislative consent from the Assembly, it remains our view that it a political requirement to gain that consent and this will be top of our agenda in any post-election negotiations.
“That agenda will also include gaining special status for Northern Ireland in the event of Britain leaving the EU.
“Today’s judgement is particularly serious given the fact that it is being suggested that the unelected, unrepresentative House of Lords will be permitted a vote yet the devolved regions will not.”
Mr Eastwood said he welcomed the part of the judgement which ensures that a vote in Westminster will be required to give consent on the triggering of Article 50.
“We will submit our own amendments and support any other amendments which protect our interests,” he said, adding:
“We will vote against any Bill which triggers Article 50. I would strongly urge all pro-Remain MPs to join us in this action.
“Last week Theresa May set out her vision for a Tory hard Brexit which, if left unchallenged, will mean a hard border in Ireland.
“Everyone on this island has a responsibility to ensure that this does not happen. It would prove devastating both politically and economically. That includes the Sinn Fein MPs who do not take their seats at Westminster.
“If Sinn Fein are serious about new leadership they cannot shirk their responsibility to the people of Ireland and should therefore take their seats to vote against Article 50.”