The Northern Ireland Protocol is lawful, the Court of Appeal in Belfast has upheld.

Unionists regard the post-Brexit trade arrangements, which see checks on goods arriving into Northern Ireland from Great Britain, as a border in the Irish Sea.

The legal challenge is another aspect of Unionist action against the Protocol, taken in the name of TUV leader Jim Allister, former Brexit Party MEP Ben Habib, and Baroness Hoey, among others.

However, that received a blow on Monday when the Court of Appeal in Belfast dismissed challenges pursued in the name of Unionists and Brexiteers from across the UK.

Senior judges upheld the ruling last June by Mr. Justice Colton, rejecting arguments that the Protocol breached the terms of the 1800 Acts of Union and the 1998 legislation that underpins the Good Friday Peace Agreement.

An adjoined case was taken by Belfast pastor, Clifford Peeples. Appeals in both cases were dismissed.

Lady Justice Keegan said the senior judges determined none of the legal arguments prevail, and accordingly the appeals were dismissed, and the decision of the trial judge affirmed.

Addressing the Court of Appeal on Monday, Lady Justice Keegan said the judicial review applications were out of time, but an extension was granted because “they raise issues of constitutional importance”.

She continued: “It is in the public interest that these issues be considered and determined by the highest court in this devolved administration.”

She said the European Union Withdrawal Act, which includes the Protocol, the Acts of Union and the Northern Ireland Act, are all of a constitutional character, adding the issue is the interplay between them and how they should be interpreted.

In the ruling, senior judges ruled that while the Withdrawal Act conflicted with the Acts of Union, Parliament knew the legislation involved and acted lawfully in enacting the latter.

They also found that the Northern Ireland Act 1998 “has no impact on the legality of the changes enacted by the Withdrawal Agreement”.

In terms of the argument of a democratic deficit being caused by European laws that the people of Northern Ireland had no say in being imposed on them, the judges held that the justification for differential treatment “fell within the choices made in a ‘highly-visible, political process’,” and rejected this ground of appeal.

Meanwhile, no merit was found in any of the additional arguments raised by Mr. Peeples.

DUP leader Sir Jeffrey Donaldson said the legal challenge will now go to the Supreme Court.

Sir Jeffrey, whose party’s first minister, Paul Givan, resigned over the impact of the Protocol, insisted it is undermining the position of Northern Ireland within the UK.