Yesterday Alex Bell, formerly head of policy and speechwriter to Alex Salmond, wrote in the Guardian that Theresa May had “called Sturgeon’s bluff” over Brexit.

As he pointed out, the Prime Minister’s high-profile speech had set out that the UK would be leaving the Single Market. Nicola Sturgeon had previously indicated that this would lead her to seek a re-run of 2014’s referendum on Scottish independence.

That was already a climbdown – the initial cause was protecting Scotland’s place in the EU – but as Bell notes, the First Minister appears to have backed off again, simply saying that such a poll was now more likely even than it had been before. He adds that Sturgeon “has to name a date for another independence referendum” or risk seeing her authority bleed away.

But that’s where a flaw slips into his analysis, or at least his language: the First Minister can’t “name a date”. The constitution is a reserved issue, as I’ve pointed out before. Sturgeon can demand a second referendum, but she can’t call one.

This fact is very often met with the observation that Westminster is very unlikely to block a second referendum should the Scottish Government call for one, so we’re justified in behaving as if the power were Sturgeon’s to command. But even if the Government were presumed to grant a referendum if requested – and I agree they would – that latter assumption is wrong.

Before any vote Westminster and Holyrood would need to negotiate, just as last time. Some of the issues could likely be decided by 2014’s precedent but the idea that neither side will try to implement lessons they learned last time out is surely for the birds. Likewise the two parties will need to agree on a timetable, the Scottish Government can’t just pick one that suits them best.

Delay means no rushing through a decision during a short-term emotional surge, and longer for the nationalists’ new proposals for how independence would work (should they ever emerge) to be scrutinised and subject to events.

Of course, some will argue that May had better just accede to all of Sturgeon’s initial demands or face a reckoning at the ballot box. But most of those people predicted that such a response would follow Brexit, and many are in any case simply commentators who want the SNP to win.

The idea of a seething Scottish public just waiting to take offence on the Nationalists’ behalf has been a powerful tool in the SNP arsenal, but the available evidence suggests that those voters who do feel that way are already voting for them.

Not to mention the fact that David Cameron’s experience has already highlighted the poor yields of over-generous concessions in this field, or that May seems to be a more robust unionist even than he.

Would any of this matter? It could well, if the result is close – and absent a bolt from the blue and a huge swing towards independence ‘close’ looks to be the trigger Sturgeon will need to settle for if a referendum is to be chanced at all.

And should the battle be lost a second time? The Canadian example suggests that central government would be a lot more assertive about its constitutional prerogatives before it was challenged a third.