On 26 June 2016, following the UK referendum, the government there gave its Brexit notice to the EU as per Article 50 of the TEU, which requires it to perform an “orderly withdrawal”. 

Following lengthy negotiations, the terms of the Withdrawal Agreement were agreed on 19 October 2019. The Withdrawal Agreement, an international treaty, included the Ireland and Northern Ireland Protocol and similar protocols for Cyprus and Malta.

Both were transposed into UK domestic law (by the EUWA Act 2018) by royal assent on 23 January 2020, and the Withdrawal Agreement was ratified on 29 January 2020, but allowing for a ‘transition period’ ending 31 December 2020.  

Brexit has been UK law since 1 January 2021. Agreed by its domestic law, the Withdrawal Agreement and the Northern Ireland Protocol, is that Northern Ireland shall remain in the EU Single Market for the life of the Northern Ireland Protocol, which will die on 1 January 2025 unless extended for a further four or eight years.

Extension requires “democratic consent” by a majority of the MLA’s “present and voting” in the Northern Ireland Assembly, which seems unlikely as it is currently dissolved, although some 52 of its 90 elected MLAs do want the NIB extension.

International treaty and domestic-law duty conflicts

In addition to the current invasion of Ukraine by Russia in clear breach of international law, the disorderly and delayed implementation of the Brexit treaty duties is causing legal analysis of conflicts between international treaty duties and internal law.

What is a breach?

The sincere observance by all State parties of their international treaty duties determines their reputation. After WW1, a “war to end all wars”, the Versailles Treaty and its protocol, the Covenant of the League of Nations, both effective from 10 January 1922, had short lives as their functions and objectives of security and peace by diplomacy became redundant.

The United Nations Charter of 1946, as WW2 ended, however, recited its clear purpose, ”...to save succeeding generations from the scourge of war ...”, and the consequential need for sincere cooperation and good faith by its parties. Article 26, therefore, of the Vienna Convention on the Law of Treaties 1969, headed: ‘Pacta sunt servanda’, provides that: “Every treaty in force is binding upon the parties to it, and must be performed by them in good faith.”

Its Article 27 states: “A party may not invoke the provisions of its internal law as justification for its failure to perform a treaty.” Non-compliance is a breach of the rule of law.  

Prima-facie breaches

There are increasing prima facie breaches of the UK’s duties under local and international law. Outstanding are delays and non-cooperation in implementation of the law agreed by Brexit and by the increasing number of unforeseen unilateral measures taken by the UK Government and its executive, contrary to the Withdrawal Agreement without the prior consent of the EU.

Such measures include extending the transition period beyond 31 December 2020 and the failure to apply many EU laws as it particularly agreed (in breach of Article 12(1) of the Northern Ireland Protocol which also lists many applicable EU laws in its Annex 5), so as to honour and keep secure the EU legal standards for manufactured goods and agricultural goods entering the EU through its Northern Ireland back door, which failure is thereby jeopardising the EU’s integrity.  

UK’s unilateral changes to its treaty duties

The new Northern Ireland Protocol Bill, without prior consent, notice or any assistance first being sought from its good friends in the EU, was introduced to the House of Commons by the UK Government on 13 June 2022, and unilaterally scraps the Northern Ireland Protocol duties of the UK. 

Rather than complying with what it has agreed in the Withdrawal Agreement and Northern Ireland Protocol, namely that UK law will be different for that part of the UK which is Northern Ireland, and which should now have a customs and other controls border at its ports to respect the EU integrity, section 1 of its bill ”... provides that enactments, including the Union with Ireland Act 1800 and the Act of Union (Ireland) Act 1800, are not to be affected by the Northern Ireland Protocol that does not have effect in the United Kingdom.”

This bill seeks to counteract the judgement of the Court of Appeal of Northern Ireland, delivered by Lord Chief Justice Keenan on 14 March 2022, before its appeal to the Supreme Court has been decided, in which it is held that the Withdrawal Agreement and its Northern Ireland Protocol and the EUWA Act 2018 implementing both into UK law “prevail over any previous historic UK primary constitutional legislation, especially the Act of Union 1800” [James Allister and Ors v The Secretary of State for Northern Ireland].

Conflicts between rule of law and UK law

UK law offers less accessibility to certainty, especially in relation to its duties to comply with the rule of law. This is not assisted by its indistinct, unwritten constitution and the status of its primary, constitutional legislation and how this is so categorised. Lord Justice Keenan stated (paragraph 123 in re Allister): 

“... Parliament may place limits upon its own sovereignty by virtue of some acts of Parliament such as the European Communities Act 1972, and the Human Rights Act 1998. However, there has not been a court case where judges in the UK have ruled that an act of Parliament is contrary to the rule of law and therefore unconstitutional”.

We have seen that this is contradicted by Article 27 of the Vienna Convention on the Law of Treaties 1969, by which the rule of law cannot be revoked or overridden by domestic legislation. 

Exclusive jurisdiction 

The Withdrawal Agreement is a treaty between UK and EU. It is governed by EU law, and the CJEU has exclusive jurisdiction to determine any issues or breaches arising from it following failed talks, negotiations and efforts by its special committee and joint-committee structure.

Despite the uncertainties about which UK statutes have primary status as constitutional statutes, the inaccessibility to fundamental legal rights that are uncodified, and the fact that the UK Supreme Court and its predecessors have never yet ruled that any act of Parliament that is found to be contrary to the rule of law is thereby unconstitutional, international law to which the UK is party prevails over any conflicting UK law provisions, which cannot justify non-compliance with the rule of law. Articles 26 and 27 of the Vienna Convention 1969, to which the UK is party, states this clearly: “Pacta sunt Servanda.”

(The above is an extract from Duncan Grehan’s feature article on this topic, which will appear in our Aug/Sept Gazette.)