Northern Ireland protocol: UK Supreme Court rejects challenge to legality

Contentious trading arrangements challenged by collective of unionists and Brexiteers

A legal challenge against the Northern Ireland protocol ended on Wednesday after the UK Supreme Court ruled the controversial legislation was lawful.

A panel of five judges unanimously dismissed the appeal on all grounds.

The case taken by group of unionists and Brexit supporters — including Traditional Unionist Voice (TUV) leader Jim Allister, former first minister and DUP leader Arlene Foster and former Brexit Party MEP Ben Habib — had previously been defeated in the High Court in Belfast and the Court of Appeal.

Acts of Union 1800

They sought to challenge the legality of the protocol on three grounds, arguing that it conflicted with Article Six of the Acts of Union 1800, which states that all parts of the UK should be on an equal footing, that Northern Ireland’s constitutional position had been changed without the referendum stipulated in the Northern Ireland Act 1998, and there was no requirement for cross-community approval in a future Assembly vote.


The Supreme Court found that while article six had been “modified” by the protocol it had not been repealed, and this was legal as this superseding legislation was the expressed wish of the sovereign parliament.

“The most fundamental rule of UK constitutional law is that parliament, or more precisely the Crown in parliament, is sovereign and that legislation enacted by parliament is supreme,” said Lord Stephens.

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Regarding the Northern Ireland Act — the legislation which brought the provisions of the Belfast Agreement into UK law — this was dismissed as the court said it had ruled in a previous case that the requirement for a referendum only applied in one particular case, whether Northern Ireland remained in the UK or became part of a united Ireland.

The appellants claim that the requirement for cross-community support for the protocol in a future vote in the Assembly was also dismissed as it had been superseded by subsequent, lawfully-made legislation.

Sinn Féin vice-president, and the North’s first minister-designate, Michelle O’Neill welcomed the ruling and said the protocol was “lawful, but also necessary to limit the damage done by Brexit. No credible alternative exists, we need to make it work better for everyone”.

DUP leader Jeffrey Donaldson, who was at the Supreme Court for the ruling, said afterwards that the cases had “served to highlight some of the reasons why unionists have uniformly rejected the protocol” and said the UK government “must consider this judgment, their own arguments to the court and take the steps necessary to replace the protocol with arrangements that unionists can support”.

Post-Brexit trading

The judgment comes amid mounting speculation that the EU and UK are preparing to agree a deal on the Northern Ireland protocol, the post-Brexit trading arrangement which avoided a hard border on the island of Ireland by placing an economic border in the Irish Sea.

Mr Donaldson re-emphasised that his party’s boycott of the Assembly and Executive in protest against the protocol — which unionist parties argue has undermined the North’s constitutional position within the UK — will continue until “the protocol is replaced with arrangements that restore NI’s place in the UK internal market and our constitutional arrangements are respected”.

The Northern Secretary is due to hold further talks with Northern Ireland’s five largest political parties on Thursday.

Freya McClements

Freya McClements

Freya McClements is Northern Editor of The Irish Times