The leaders of Scotland, Wales and Northern Ireland are set to join forces in an unprecedented push for greater self-determination, with the three first ministers expected to sign a joint declaration asserting their right to hold referendums on their constitutional futures. Scottish First Minister John Swinney, Welsh First Minister Rhun ap Iorwerth and Northern Ireland First Minister Michelle O'Neill are due to meet in Cardiff on Monday for talks that could intensify an already charged debate over the future of the United Kingdom.
The summit brings together leaders from three devolved nations whose governments are now headed by parties supporting major constitutional change. While their political objectives and the legal routes available to them differ considerably, the meeting marks an unusual attempt to coordinate demands for greater control over their respective constitutional futures. The leaders are expected to sign a memorandum of understanding and discuss cooperation in areas including the economy, energy, relations with Europe, international affairs and self-determination.
Three nations, different routes
The constitutional positions of Scotland, Wales and Northern Ireland are not identical, making the proposed declaration politically significant but not by itself sufficient to trigger independence votes. Scotland held an independence referendum in 2014, when voters chose by 55 per cent to 45 per cent to remain in the United Kingdom. The Scottish National Party has continued to campaign for another vote, arguing that political circumstances have fundamentally changed since then, particularly following Brexit.
Scotland voted strongly to remain in the European Union in the 2016 Brexit referendum even as the UK as a whole voted to leave. The legal position was clarified by the UK Supreme Court in 2022, when it ruled that the Scottish Parliament could not legislate unilaterally for an independence referendum because the question concerned matters reserved to Westminster.
Northern Ireland operates under a different constitutional framework. The 1998 Good Friday Agreement provides a mechanism for a referendum on Irish reunification, commonly known as a border poll. The authority to call such a vote rests with the British government when it appears likely that a majority would support Northern Ireland leaving the UK and joining a united Ireland.
Wales, meanwhile, has historically recorded substantially lower support for independence than Scotland, although Plaid Cymru's rise has brought the constitutional question closer to the centre of Welsh politics.
Pressure mounts on Westminster
The Cardiff gathering comes at a sensitive moment for the British government, with Prime Minister Andy Burnham facing renewed demands to clarify when Westminster would permit another Scottish independence referendum.
Swinney has pressed for a formal route to a second vote if clear democratic support emerges in Scotland. Burnham has indicated that a referendum could ultimately be considered where there was clear consensus, but has subsequently pushed back against demands for an automatic mechanism similar to Northern Ireland's border-poll provisions.
The Scottish government has argued that decisions over Scotland's constitutional future should ultimately rest with Scottish voters rather than Westminster.
In Wales, ap Iorwerth has also demanded a substantial expansion of devolved authority, including powers over policing and justice. He has, however, rejected suggestions that his immediate objective is simply to engineer the break-up of Britain, arguing that his priority is strengthening Wales while maintaining independence as a longer-term political ambition.
Trump remarks revive Irish unity debate
The constitutional debate has also been sharpened by US President Donald Trump's intervention on Irish reunification during his visit to Ireland.
Trump said he would “love” to see a united Ireland, an unusually direct intervention by an American president into one of the UK's most politically sensitive constitutional questions.
Downing Street subsequently said its position remained unchanged, stressing that there was currently no evidence of majority support in Northern Ireland for a border poll and therefore no basis for calling one.
Trump's remarks drew criticism from unionist politicians in Northern Ireland, who insisted that the territory's constitutional future should be determined by its people under the provisions of the Good Friday Agreement.
For O'Neill and Sinn Féin, however, Irish reunification remains a central political objective, making the Cardiff meeting another forum in which the question of constitutional change can be linked with similar debates elsewhere in Britain.
Union faces renewed test
The summit does not mean the break-up of the UK is imminent. Significant legal, political and electoral barriers remain, while public opinion on independence varies substantially among the three devolved nations.
Yet the meeting is notable because constitutional movements that have traditionally pursued their objectives separately are attempting to establish common ground around the principle that voters in each nation should be able to determine their own future.
The UK comprises England, Scotland, Wales and Northern Ireland, with devolved governments exercising varying degrees of authority outside England. Westminster retains control over several crucial areas, including defence, foreign policy and major constitutional questions.
Brexit has added another layer of tension to that settlement, particularly in Scotland and Northern Ireland, where questions over relations with the European Union have become intertwined with debates over sovereignty.
Monday's Cardiff summit is therefore unlikely to produce an immediate route to independence for any of the three nations. But by presenting referendum rights and self-determination as shared demands, the leaders of Scotland, Wales and Northern Ireland are preparing to place fresh pressure on Westminster over who ultimately gets to decide the future shape of the United Kingdom.