A challenge to Brexit has broken new ground in becoming the first civil case in Northern Ireland’s history to be referred to the UK Supreme Court by the Court of Appeal, lawyers have said.

Ciaran O’Hare of McIvor Farrell Solicitors has acted for victims’ campaigner Raymond McCord in a challenge to the way the Government intends to invoke Article 50 of the Treaty on European Union to trigger withdrawal from the EU.

On Friday, the case came before the Lord Chief Justice, Sir Declan Morgan, in the Court of Appeal, who ruled that the key argument in Mr McCord’s case be referred to the UK Supreme Court.

Mr McCord’s legal team, which includes senior counsel Ronan Lavery QC and junior counsel Conan Fegan BL, believe the case is one of the most important constitutional cases ever to come before the court.

Mr O’Hare said: “This case will undoubtedly be the pinnacle of my career because as a lawyer, it doesn’t get any bigger than this.

“The work to get this case to where we are now has been exhausting. We have been faced with challenges every step of the way. There have been many sleepless nights simply spent thinking about the case.

“We have broke new ground and thus far successfully navigated uncharted territory. I have great respect for both Conan Fegan BL and Ronan Lavery QC and I believe the work they have done in this case has been extraordinary.”

He added: “We now look forward to making arguments in the Supreme Court in early December. It is a privilege to be involved in a case of such magnitude and although this is Mr McCord’s case, we are of the view that this case is representative of the people of Northern Ireland.”