There is an argument that the road to Brexit started with the Maastricht treaty that was signed in 1992, for it was then that the European Union was established, as the next stage of the European Economic Community and its single market that the UK government of Margaret Thatcher and Lord Cockfield had enthusiastically helped to fashion. Following the treaty of Maastricht, successive but always reluctant UK governments—both Conservative and Labour—sought carve-outs and opt-ins without ever going to the trouble of making a positive case for the European project to the electorate.
But the actual shape of Brexit owes more to another international agreement: the Good Friday Agreement of 1998. This instrument has restricted the free movement of the government of the United Kingdom. It has obliged ministers and officials in Whitehall to agree to things they otherwise would have rejected, and it has prevented MPs in Westminster from asserting their purportedly regained sovereignty.
The Good Friday Agreement was—and remains—a remarkable document. This should not be surprising, as it helped end the horrific Troubles in northern Ireland. It did so by establishing a special political situation. Northern Ireland was no longer just another part of the United Kingdom where the will of London had ultimate, absolute power. Instead, things had to be done on a cross-community basis and with regard to the government—and thereby the people—of Ireland.
The agreement has had many practical political consequences. For example, the primary reason that Conservative ministers since 2010 have not been able to repeal the Human Rights Act 1998, despite numerous promises and proposals, is that the GFA provides that the European Convention on Human Rights must be directly enforceable in the courts of Northern Ireland. This obstacle to repeal has proved insurmountable. And so, as and when the Conservatives finally leave office, the Human Rights Act will still be there and the Conservatives will not be.
This is not merely an academic point. The importance of enforceable European convention rights in Northern Ireland is very much a live issue, as a recent case brought by the Dublin government shows. The parliament at Westminster may, according to constitutional doctrine, claim sovereign power, but that power is strictly limited when it comes to Northern Ireland. In this way, the GFA is more practically significant as a constitutional instrument than, say, Magna Carta.
But there are other effects of the Good Friday Agreement. This week, the High Court in Belfast not only ruled against the UK government, the court even disapplied eight provisions of an Act of Parliament from having effect in Northern Ireland. And, furthermore, that court did so by relying on EU law as retained in Northern Ireland after Brexit. This was the sort of thing which Brexit was supposed to have made impossible.
Yet the court’s decision was made possible by the Brexit withdrawal agreement negotiated, signed and implemented by the government of the United Kingdom: a withdrawal agreement that was, in turn, necessitated by the special political situation in Northern Ireland created by the GFA.
The Act of Parliament that was disapplied in part was the controversial Illegal Migration Act 2023—the title of which can now be seen as fairly ironic, given that provisions of the Act are, well, illegal.
The judge held that the eight offending elements of the Act were a breach of the so-called Windsor Framework (the name given to the renegotiated Northern Irish protocol, part of the Brexit withdrawal agreement). In particular, sections of the 2023 Act diminished or removed rights that exist under the EU law that still applies in Northern Ireland. This meant that, under section 7A of the Brexit withdrawal legislation, the court had the jurisdiction to set aside primary legislation passed by the Westminster parliament.
The consequence of this in policy terms is that the Rwanda policy of the UK government cannot be implemented in Northern Ireland, because asylum seekers are as much members of the community of Northern Ireland as anyone else protected under the special political and legal regime heralded by the GFA.
The story of Brexit—and now the story of the Rwanda removals policy—is in good part the story of Westminster politicians being constantly taken by surprise by the ongoing implications of the Good Friday Agreement. Just as the GFA has stopped repeal of the Human Rights Act, it also stopped a “no-deal” Brexit, as the UK government found that parliament would not permit a departure without arrangements for Northern Ireland being in place. And now the Rwanda removals policy is also stopped, insofar as it would be implemented in Northern Ireland.
At some point there will be a realisation in the government in London that Westminster and Whitehall no longer have complete autonomy in one of the constituent parts of the United Kingdom, notwithstanding constitutional doctrine and political ambition.
When this realisation occurs, then politicians in London will have to make a choice. Either they can have the brash absolutist sovereignty that they seem to crave, or they can support a continued United Kingdom of Great Britain and Northern Ireland. But so long as the Good Friday Agreement is in force, they cannot have both.
