15th September 2026
The meeting in Cardiff on Monday is more significant than simply a discussion between the three nationalist parties. John Swinney (SNP), Rhun ap Iorwerth (Plaid Cymru) and Michelle O'Neill (Sinn Féin), with Mary Lou McDonald also attending, are using the meeting to argue that Scotland, Wales and Northern Ireland have a right to determine their own constitutional futures.
They are expected to sign a memorandum of understanding setting out that position.
But it is worth separating what they are asking for now from the much bigger question of independence.
What are they actually asking Westminster for?
There are essentially three demands.
1. The right to hold a referendum
The most immediate demand is that Westminster should not be able simply to veto a democratic vote on constitutional status.
For Scotland, that means the SNP wants a route to another independence referendum. Swinney has argued that Scotland's constitutional future should be decided by the Scottish people.
For Wales, Plaid Cymru wants the same principle established, although Welsh independence is at a much earlier stage politically.
For Northern Ireland, the situation is different because the Good Friday Agreement already provides a mechanism for a border poll if the UK Secretary of State believes it is likely that a majority would vote for a united Ireland.
So they are not actually demanding one identical referendum system for all three countries. They are seeking recognition of a broader right of self-determination.
2. Westminster should prepare for possible constitutional change
This is potentially the more interesting demand.
The leaders want the UK Government to recognise that independence or Irish reunification is no longer something Westminster can simply dismiss as impossible.
In practical terms, that means preparing for negotiations over things such as assets and liabilities, public services, borders, energy, pensions, defence and international relationships if any of the countries eventually votes to leave the UK.
Scotland has already produced a detailed model for what such negotiations could involve. Its previous Scotland's Future document, for example, envisaged negotiations over UK assets and liabilities, delivery of services, public-sector employees and cross-border arrangements.
3. A different relationship between the four nations
There is a bigger constitutional argument underneath today's meeting.
They are effectively saying that the UK should no longer operate on the assumption that Westminster ultimately controls the constitutional destiny of Scotland, Wales and Northern Ireland.
That does not necessarily mean independence tomorrow.
It could mean a much more federal or confederal UK, much greater devolution, or eventually separate states.
There is an important complication
The three cases are very different.
Scotland voted 55% to remain in the UK in 2014, and the SNP wants another referendum.
Wales has never held an independence referendum and support for independence remains considerably lower than in Scotland.
Northern Ireland already has a constitutional mechanism under the Good Friday Agreement which is fundamentally different from Scotland and Wales. The issue there is not simply "independence" but whether Northern Ireland should remain part of the UK or become part of a united Ireland.
That makes today's agreement politically powerful as a joint statement of principle, but it doesn't mean that the three countries are at the same stage.
And there is an interesting twist involving Burnham
This is where I think today's story becomes particularly interesting in light of your earlier article about Labour's rural reset.
Andy Burnham has not agreed to their demands. The UK Government continues to resist an immediate second Scottish independence referendum and says the circumstances for a Northern Ireland border poll do not currently exist.
But Burnham has made comments about Scotland's constitutional position that nationalists believe have opened the door to a different way of thinking about the Union.
That is why Monday's Cardiff meeting matters.
The nationalists are effectively saying:
If the UK is genuinely a voluntary union, Westminster cannot permanently refuse to allow one of its nations to ask its own people whether they want to remain.
That is a much more fundamental argument than simply asking for another referendum.