Is the United Kingdom beginning to come apart? 

Scotland, Wales and Northern Ireland are now led by parties that see their future in Europe. But leaving the United Kingdom is one thing. Getting back into the European Union is another.

Author: Balazs Lang

For decades, the break-up of the United Kingdom was mostly discussed as a possibility rather than something that might actually happen. Scottish independence occasionally pushed the question into the headlines, as did the long-running debate over Irish reunification. Wales rarely featured in the conversation at all.

Brexit changed that.

Today, Scotland, Wales and Northern Ireland are all led by parties that want a different constitutional future from the one offered by Westminster. And on 14 September, their leaders came together in Cardiff to make that point publicly. John Swinney of the Scottish National Party, Rhun ap Iorwerth of Plaid Cymru and Michelle O’Neill of Sinn Féin signed a memorandum declaring that Scotland, Wales and Ireland should have the right to decide their own constitutional futures. They also made clear where they believe those futures lie: in the European Union.

The document itself does not change Britain’s constitution. It cannot force Westminster to hold a referendum and it certainly does not mean that the United Kingdom is about to disappear. But politically, it matters. For the first time, the nationalist movements governing Scotland, Wales and Northern Ireland are openly presenting their constitutional ambitions as part of a wider argument about Britain’s future.

It raises an obvious question. Could Brexit eventually produce the opposite of what its supporters intended? Could parts of the United Kingdom one day leave Britain in order to return to Europe?

Three nations, three different routes

The first thing to understand is that Scotland, Wales and Northern Ireland cannot simply vote among themselves to leave the United Kingdom. Their constitutional situations are very different.

Northern Ireland has the clearest legal route. The 1998 Good Friday Agreement established the principle that Northern Ireland’s constitutional status depends on the consent of its people. British law allows for a border poll if the Secretary of State believes that a majority is likely to support Irish reunification. If Northern Ireland voted to join the Republic of Ireland, London and Dublin would have to work out how that decision should be implemented.

Scotland does not have the same right. The UK Supreme Court made that clear in 2022 when it ruled that the Scottish Parliament could not organise its own independence referendum without Westminster’s agreement. That means another legal Scottish referendum would, under the current system, require London to cooperate.

There is already a precedent. Before the 2014 referendum, Westminster temporarily gave the Scottish Parliament the power to hold the vote. Scotland then chose to remain in the United Kingdom by 55.3 to 44.7 per cent. A future referendum would probably require a similar political agreement.

Wales faces much the same problem. The Senedd cannot simply organise a binding independence referendum and declare Wales independent. So despite the language coming from Cardiff, London still controls much of the constitutional machinery.

Scotland could have the easiest road back to Europe

If Scotland did eventually become independent, joining the European Union would be entirely possible. But it would not happen automatically. Scotland could not simply announce independence on Friday and wake up as an EU member on Monday.

It would become a new sovereign European state and would have to apply for membership under Article 49 of the Treaty on European Union. That means going through the EU accession process and meeting the same basic political, economic and legal requirements expected of other candidates.

Scotland would, however, start from an unusually strong position. It was part of the European Union until Brexit. Its institutions are already those of a mature democracy and much of Scottish law remains closely connected to EU rules. The Scottish government has also deliberately tried to maintain alignment with European legislation since Brexit.

In practical terms, Scotland would probably have considerably less work to do than many countries that begin the accession process from outside the European legal and institutional system. But there would still be negotiations. Questions about currency, borders, trade, fisheries, public finances and Scotland’s relationship with the remaining United Kingdom would all have to be settled.

And there is another important hurdle: EU membership ultimately requires the agreement of every existing member state. So Scotland would have two negotiations to complete. First with London over independence. Then with Brussels and the EU’s member states over membership. The first could easily prove harder than the second.

Wales has much further to travel

Wales is a different story. Plaid Cymru’s rise has changed Welsh politics, and the idea of independence has become considerably more mainstream than it was a generation ago. But there is still no clear majority for it. Polling around the Cardiff meeting put support for Welsh independence at roughly one third of voters, noticeably below the level seen in Scotland.

Rhun ap Iorwerth’s position reflects that reality. While John Swinney continues to demand another Scottish independence referendum and Michelle O’Neill talks openly about an Irish unity vote, the Welsh leadership has not set an immediate timetable for an independence referendum. For Wales, therefore, EU membership remains a distant question.

First, supporters of independence would have to build a lasting majority for leaving the UK. Then they would have to secure a legal route to a referendum. If independence won, Wales would have to negotiate separation from the UK and establish itself as a sovereign state. Only then could Cardiff apply to join the European Union.

There is nothing in EU law that would prevent an independent Wales from applying. The difficult part is getting to independence in the first place.

Northern Ireland is completely different

Northern Ireland is the most interesting case because it would not necessarily have to apply to join the EU at all. If a border poll produced a majority for reunification, Northern Ireland would join the Republic of Ireland. Ireland is already an EU member.

So unlike an independent Scotland or Wales, Northern Ireland would not be creating a new state and then asking Brussels for membership. It would become part of an existing EU country. There would obviously be enormous political, economic and constitutional questions to settle. Irish reunification would be one of the biggest changes in modern British and Irish history. But the legal route already exists. That is what makes Northern Ireland different.

Scotland has a strong independence movement but no guaranteed route to another referendum. Wales has a growing independence movement but currently lacks majority support. Northern Ireland has an internationally recognised mechanism for changing its constitutional status, but there is not yet clear evidence of a majority demanding reunification.

Brexit changed the argument

This is where Brexit becomes important. Scotland voted strongly to remain in the European Union in 2016. Northern Ireland also voted Remain. Both nevertheless left because the United Kingdom as a whole voted for Brexit.

That created a political argument that did not really exist before. Scottish nationalists can now say that independence offers a route back into Europe. Irish nationalists can argue that reunification would automatically reconnect Northern Ireland fully with an EU member state. And Plaid Cymru increasingly presents Welsh independence as part of a European rather than simply British future.

There is an irony here. Brexit was partly sold as a project to restore British sovereignty. It may also have strengthened movements arguing that sovereignty should instead belong to Scotland, Wales and Ireland.

So could the United Kingdom actually break apart?

Yes, constitutionally it is possible. But it is unlikely to happen quickly, and certainly not because three leaders signed a memorandum in Cardiff. The three countries face very different political realities.

For Scotland, the crucial battle is obtaining another referendum. If Scotland became independent, there is a clear route to applying for EU membership. For Wales, the independence movement first needs to persuade considerably more Welsh voters. For Northern Ireland, the mechanism already exists, but a border poll would only become relevant if there were convincing evidence that public opinion had moved towards reunification.

So there is no single road towards the break-up of Britain. There are three roads. And they are moving at very different speeds.

What has changed is the political direction

Britain now has three devolved governments led by parties that do not regard the United Kingdom in its present form as the final destination of their nations. Even more strikingly, all three increasingly look towards Europe when describing what might come next.

The Cardiff memorandum will not break up Britain. But it tells us something about how dramatically British politics has changed since Brexit.

Ten years ago, the great constitutional question was whether Britain should remain inside the European Union. The next one may be rather different. Whether the United Kingdom itself can remain united.

Cover photo credit: Balazs Lang

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