Raymond McCord, a prominent victims’ rights campaigner whose son was killed by loyalist paramilitaries in 1997, lodged his application for judicial review last month. He has been provided with legal aid for the challenge.

A cross-community group of MLAs will also go ahead with an additional challenge along similar lines, which will be heard on the same day.

Mr McCord will argue that Brexit would contradict the UK’s international obligations under the Good Friday Agreement, and any notification under Article 50 would also require a mandate from MPs.

His challenge has welcomed the support of Dermot Ahern, who was a member of the Irish Government during the negotiation of the Good Friday Agreement and a key negotiator on the St Andrews Agreement.

Mr Ahern said he was “aghast at the potential negative fallout for this island as a result of the vote, not least the implications for the Good Friday agreement architecture”.

He added: “I think during my time as Minister for Foreign Affairs, I met Mr McCord as he campaigned as a result of his son’s murder.

“I’ve been aware from media reports about his Brexit legal challenge, and I wish him well in this.”