Prime Minister Andy Burnham is facing pressure to ensure that any written constitution for the UK includes a clear and legally defined pathway for Scotland to leave the Union.
The warning comes as constitutional reform moves up the political agenda, with campaigners and Scottish voices insisting that if the UK ever codifies its governing rules into a written document, the right to self-determination cannot be left out or buried in vague language.
The argument is straightforward. If you are going to write down the rules of how the UK works, you cannot ignore the fact that Scotland has repeatedly debated its place within it. Leaving out a clear route to independence would not be a neutral act, it would be a deliberate one.
Scottish independence supporters have long argued that one of the biggest obstacles to a second referendum has been the political and legal uncertainty around how it could happen. Westminster has consistently held that it controls whether a legally binding vote can take place, a position that frustrates many in Scotland who believe the decision should rest with the Scottish people.
A written constitution, they argue, could change that entirely. If the right to hold an independence referendum were enshrined in law, no future prime minister could simply refuse to engage with the question the way recent governments have.
Burnham, who has positioned himself as a reforming figure open to reshaping the UK’s constitutional settlement, is being urged not to treat this as a minor footnote. Constitutional experts and pro-independence voices alike say that a written constitution which sidesteps the question of secession would lack credibility and would likely deepen rather than ease tensions between Edinburgh and London.
The debate also touches on broader questions about what kind of Union the UK actually is. Is it a voluntary partnership of nations that can be renegotiated, or is it a fixed arrangement where the centre holds all the cards? How a written constitution answers that question would say a great deal about the kind of democracy the UK claims to be.
For Scotland, the stakes are high. The SNP and wider independence movement have spent years arguing that the current setup is fundamentally undemocratic when it comes to Scotland’s ability to choose its own future. A written constitution that locks in Westminster’s veto without any clear process for change would likely be seen as a step backwards, not forwards.
On the other side, Unionist voices will be wary of any constitutional text that makes it easier for Scotland to leave. They will argue that building in a formal exit mechanism risks encouraging separatism and undermining the stability of the Union itself.
Burnham will need to navigate that tension carefully. Constitutional reform is the kind of issue that sounds dry but carries enormous real-world consequences, particularly for Scotland where questions of sovereignty and democratic rights are felt deeply.
What happens next remains to be seen. A written UK constitution is not something that gets drafted overnight, and any serious attempt to produce one would require extensive consultation across all four nations. But the message being sent to Burnham is clear enough. If Scotland is going to be part of this process, its right to leave must be part of the document.