A decision to refer a legal challenge to the Northern Ireland Protocol to the UK’s highest court has been welcomed by unionist politicians.
Northern Ireland’s Lady Chief Justice Dame Siobhan Keegan has granted leave to appeal against a ruling that the post-Brexit trading arrangement is lawful.
The case will now be considered by Supreme Court justices, although no date has yet been set.
Unionists regard the protocol, which sees checks on goods arriving into Northern Ireland from Great Britain, as a border in the Irish Sea.
The legal case has been taken in the name of TUV leader Jim Allister, former Brexit Party MEP Ben Habib and Baroness Kate Hoey among others. A separate challenge is being taken by a loyalist pastor, Clifford Peeples.
Last year, their arguments were rejected in both the High Court and Court of Appeal in Belfast.
However, High Court judge Mr Justice Colton did rule that the Withdrawal Agreement Act which led to the protocol conflicted with Article 6 of the Acts of Union which ensures unfettered trade between Great Britain and Northern Ireland but considered that the new legislation overrode the older laws.
This is one of the points which will be considered at the Supreme Court.
Mr Allister said: “I am delighted the Court of Appeal has granted leave to proceed to the Supreme Court.
“This is a clear indication and recognition of the fact that there are significant legal and constitutional issues to be resolved by the highest court in our land.
“I pay tribute to our legal team and the supporting public who have got us to this point and look forward to definitive rulings which go to the very heart of Northern Ireland’s position as a threatened integral part of the UK.
“This is a battle which must be fought both legally and politically.”
DUP representative Diane Dodds said the protocol was not supported by a single unionist party.
She added: “The Irish Sea Border must go. It doesn’t represent the best of both worlds. It separates us from our main market, within our own country.
“Far from protecting political stability in Northern Ireland, it remains an existential threat to our place within the United Kingdom. It must be opposed both politically and legally.
“We have supported the joint unionist legal action and welcome this next step to the Supreme Court.”
She added: “The protocol has driven up haulage costs between GB and NI, frustrates business and individuals from trading with our most important partner – Great Britain and threatens the supply in the middle of a health pandemic.
“Unchanged, it can only get worse, but we have made progress in convincing many of the merits of our case.
The EU can be in no doubt that the protocol casts a long shadow over Northern Ireland’s political arrangements
“The Government knows the protocol does not enjoy unionist support.
“The EU can be in no doubt that the protocol casts a long shadow over Northern Ireland’s political arrangements.”
Last year, the DUP first minister Paul Givan resigned in protest over the impact of the protocol, with his party leader Sir Jeffrey Donaldson insisting it is undermining the position of Northern Ireland within the UK.
A number of protest rallies featuring unionist and loyalist leaders have been held at locations across Northern Ireland in opposition to the protocol.
The Westminster Government and the EU remain locked in negotiations over the trading arrangements.
Last week, it was reported that ministers are preparing legislation giving them sweeping powers to tear up the protocol in the Withdrawal Agreement.
Prime Minister Boris Johnson has said the post-Brexit arrangement “does not command the confidence of a large part” of the population in Northern Ireland.