The defeat in the High Court in Belfast for the unionist legal challenge to the Northern Ireland Protocol is not surprising. But even if the Court of Appeal fails to support them, the challenge and the ruling have helped to illustrate the skewed legal playing field on which the pro-UK side is fighting.

It does this in two ways. First, it highlights the interpretive double-standard applied to the provisions of the Belfast Agreement. Second, it shows how the phenomenon of judges inventing constitutional principles is both iniquitous and dangerous to the Union.

It is extremely difficult to imagine that David Trimble and the Unionists thought they were signing up to any such thing

The former point has been a problem since the beginning of the Brexit process, when Theresa May’s hapless government got effectively memed into a ludicrously expansive definition of its supposed obligations to nationalists under the Belfast Agreement. At the same time, unionist entitlements under the same series of documents were read as narrowly as humanly possible.

In this way, the short list of protected areas of north-south cooperation listed in the Annex to Strand Two metastasized into a fictitious entitlement to an invisible economic border, whilst the commitment not to change Northern Ireland’s “constitutional status” supposedly applies only to a formal – final? – transfer of sovereignty. On this reading, and thus far, practice, the Agreement offers unionists no other protection for Ulster’s connections to Britain at all.

On the face of it, this is an absurdly one-sided perspective. It is extremely difficult to imagine that David Trimble and the Unionists thought they were signing up to any such thing (although it is not fashionable to pay much regard to the Nobel Prize-winning co-author of the Agreement these days). But the court ruling in Belfast has brought this interpretative preference many steps closer to being legally unshakeable reality. Certainly, as yet, the government doesn’t seem to be shaking anything in response to the ruling.

For the court has held, despite Boris Johnson’s protestations to the contrary in the House of Commons, that the Government impliedly repealed part of the Act of Union when it legislated for the Protocol. Specifically, Article Six, which provides for unhindered free trade within the United Kingdom.

One might suppose that a law which not only places Northern Ireland under the jurisdiction of a foreign legislature but requires the partial repeal of one of the foundational laws of the state would qualify as “constitutional change”, and thus violate the Belfast Agreement’s provisions about Ulster’s status within the United Kingdom.

If it doesn’t, however, then it proves beyond doubt that far from offering anything like equal protection to both communities in Northern Ireland, the Belfast Agreement actually only offers deep and granular safeguards to the nationalists. 

This seems to be fine with some. Simon Hoare, the lamentable Chairman of the Northern Ireland Affairs Select Committee, struck an aggressively victim-blaming tone on Twitter: “‘We’ve lost a court case let’s shred the GFA in revenge’ is not the politics NI wants or deserves. Or was the shredding of the GFA always the end game?” To be clear, the people he’s accusing of wishing to “shred the GFA” are unionists trying to assert the rights they believe they have under it. 

This is an absurd approach to take to a document which is supposed to provide a basis for peace by offering equal respect to, and commanding equal respect from, a divided society. If the Belfast Agreement genuinely doesn’t offer at least equal protection for Northern Ireland’s links to the rest of the UK – the state it’s in, and which status is guaranteed by the Agreement not to change without NI’s consent – as it does to the Republic of Ireland, then the moral case for it is severely weakened.

Such positions are lamentable enough from a common or garden Irish nationalist. But a senior MP, let alone a nominally unionist one, ought to be wiser or at least more careful.

Likewise, the ruling illustrates one of the many problems with judge-made law. Specifically, the doctrine of “constitutional statutes”.

If you’re unfamiliar with the term, the concept is simple enough. In normal circumstances, when two Acts of Parliament conflict the later one prevails, and is considered to override the conflicting part of the earlier law. This is called “implied repeal”.

A “constitutional statute” is a special type of Act of Parliament largely invented by judges and is immune to implied repeal. 

The concept was first set out by Lord Justice Laws in Thoburn vs Sunderland City Council, better know as the “metric martyrs” case. Whilst he was primarily using it to safeguard the supremacy of EU law, he provided a list of possible “constitutional statutes” which included “the Magna Carta, the Bill of Rights 1689, the Act of Union, the Reform Acts which distributed and enlarged the franchise, the HRA, the Scotland Act 1998 and the Government of Wales Act 1998.”

Eagle-eyed readers will have already spotted that he only lists one Act of Union, when there are two. But the deeper problem is that Parliament has never legislated to the effect that a general principle of “constitutional statutes” exists, and there is no official list of what Acts enjoy this status.

There seems to be no way of knowing in advance whether an Act will qualify as “constitutional” in any given circumstance

As a result, judges are free to apply or disapply the principle seemingly at will. Thus, the Supreme Court recognised in Miller I that some statutes have a “constitutional character”, but the divisional court rules this week that the Act of Union (Ireland) 1800 does not enjoy this status – despite Laws citing at least one Act of Union in his list of examples in Thoburn.

In fact, the judge actually ruled that the Act of Union was a “constitutional statute”, but was nonetheless subject to implied repeal anyway!

Along with the double-standard on the Belfast Agreement, this contributes to a broader impression of the law being consistently read to the unionists’ disadvantage. There seems to be no way of knowing in advance whether an Act will qualify as “constitutional” in any given circumstance, and thus there are considerable grounds for suspicion that the principle was never intended for causes as unfashionable as Ulster’s unionism.

This is not the foundation for a settlement based on respect for both sides. Indeed it seems to owe far more to the attitude EU sources expressed in the Irish press during the Brexit negotiations, when they urged Theresa May to simply tell the unionists: “listen you guys, you’ve got nowhere else to go anyway, so this is what’s going to happen”.

If Boris Johnson wants to live up to his self-appointed title of “Minister for the Union”, and perhaps even salvage the Belfast Agreement, he must do much, much better.