Cardiff Was a Warning Shot. Burnham Should Treat it as an Invitation.

15 September 2026 | Rob Fellows

There’s been a fair bit of hyperventilating about what happened in Cardiff Bay on Monday, so let’s start with what it isn’t. Swinney, ap Iorwerth and O’Neill weren’t sitting around a table signing the death warrant of the United Kingdom. Nobody has suddenly given three First Ministers at a political summit the power to break up Britain before lunch.

What they were doing is cleverer than that. They were signing a declaration asserting that Scotland, Wales and Northern Ireland should each have the right to determine their own constitutional future, wrapped around a much broader agenda about the economy, energy and Europe. It’s political pressure aimed directly at Downing Street and, frankly, some of the breathless “break-up of Britain” coverage is doing half the nationalists’ job for them before anybody has cast a single vote.

But Labour would be equally foolish to shrug its shoulders and pretend nothing significant is happening. For the first time, all three devolved governments are led by parties whose ultimate political destination is outside the United Kingdom. That matters. Swinney’s suggestion that Andy Burnham could become “the final Prime Minister of the United Kingdom” is precisely the sort of line designed to make headlines, and it will. Trump deciding to join in from Dublin and muse about a united Ireland added another slightly surreal ingredient to the day, although I’m not entirely convinced Number 10 will be rewriting its constitutional strategy on the basis of presidential small talk.

My bigger concern is how Labour has handled the argument so far. Burnham told the Commons that Scotland was in “exactly the same situation” as Northern Ireland when it comes to the principle established by the Good Friday Agreement. Then, almost immediately, we started hearing that another referendum needed to be “off the table” before the next election. You can’t really have both.

If you believe in the principle of consent, say so and own it. Saying something that sounds like a principled commitment to self-determination and then rapidly retreating into “people care about growth and the cost of living” gives Plaid Cymru and the SNP exactly the argument they wanted: Westminster believes in self-determination right up until somebody might actually ask for it.

And yet, strangely enough, I think this whole episode presents Burnham with an opportunity, because when you look beyond the flags and the constitutional theatre, much of Plaid Cymru’s shopping list is remarkably practical. Crown Estate revenues, a fairer funding settlement, policing, rail and more control over decisions currently made in London. You don’t need to dismantle the United Kingdom to do any of those things.

In fact, Burnham has spent the best part of a decade making almost exactly this argument himself. Westminster hoards too much power, too much money follows that power, and too many decisions affecting communities are taken by people hundreds of miles away who often don’t understand them. His answer has consistently been to push power outwards. It’s worked rather well for him in Greater Manchester, so why not apply the same principle to the nations of the United Kingdom?

Take the argument Burnham has made about Manchester and apply it properly to Cardiff, Edinburgh and Belfast — and, while we’re at it, to the English regions too. Give away power Westminster doesn’t need. Fix funding arrangements that clearly aren’t working. Let nations and regions control more of the things that actually affect people’s everyday lives. Not because Plaid Cymru or the SNP are demanding it, but because it’s the right thing to do.

There is obviously a risk. Some will scream capitulation, and I’m under no illusion that giving Wales control of the Crown Estate or changing a funding formula will suddenly persuade a committed Scottish nationalist to start waving a Union Jack. It won’t. But constitutional politics isn’t really about the people whose minds are already made up. It’s about everyone in the middle asking a much simpler question: does this system still work for me?

That’s where Burnham has a potentially powerful answer. A United Kingdom held together by Westminster effectively saying “you’re not allowed to leave” isn’t much of a union. A United Kingdom people actively choose to remain part of because power is shared, nations are respected and the system actually delivers for them is a very different proposition.

I’ve known and supported Andy Burnham for a long time, and one of the things that has always made him politically interesting is that his argument about devolution never felt like something cooked up by a focus group. It came from watching Westminster fail places outside London and believing that decisions are generally better when they’re taken closer to the people affected by them. Now, as Prime Minister, he has the opportunity to prove he really meant it.

Cardiff isn’t the break-up of the United Kingdom. It’s a warning shot, certainly, but it might also be an invitation. The real question is whether Burnham treats it as a constitutional threat that needs to be managed, or as the moment to start building the kind of United Kingdom he’s spent years arguing for.