Next, the currency. The SNP would have to stop pretending it could simply use the pound as before. An independent Scotland could, of course, join the euro, or launch its own currency, or shadow sterling.
But it couldn’t expect to have any joint management over the Bank of England (there’s a clue in the name), nor could it expect to have any form of quantitative easing in sterling to meet its budget deficits. Financially, it would be part of the eurozone, or on its own.
Finally, markets. Scotland could join the EU, in which case it would have to accept a hard border with the rest of the UK, complete with customs checks. Or else it could join the UK’s single market, but with no say in its rule-making.
Or, alternatively, it could do neither, and make its own way in the global market, as many small economies do perfectly successfully. But it couldn’t pretend that it could have access to both the UK and the EU’s single markets, or that it could magic away the barriers to trade that independence would create.
Brexit has already shown that doesn’t work. On top of that, Scotland would have to agree that all subsidies from the UK would come to an immediate end and that all UK assets outside Scotland would remain the property of the rest of the country.
As Michel Barnier – who, come to think of it, might make an excellent negotiator for Westminster, especially given that he seems to be at a loose end – pointed out endlessly during our departure from the EU, the UK couldn’t cherry-pick which bits of membership it wanted, nor could it expect to get a better deal outside that Union than it enjoyed as a member.
The same is true of Scotland if it chooses to leave the UK. If the SNP is willing to concede those points, then there could be a referendum.
The Scottish people could make a realistic choice, stripped of the illusions spun by the Nationalists. And a vote might finally be held that would put the whole argument to rest – this time for a couple of generations at least.