From time to time it is necessary to execute a government minister to encourage the others. This is one such moment.

Hanging. Shooting. Beheading. Defenestration. Take your pick. It doesn’t matter which method you choose but the government minister who told The Guardian’s Nick Watt that “of course” there would be a deal to be done creating a sterling zone shared by an independent Scotland and the remaining parts of the United Kingdom needs to be found, summarily tried, and executed.

Game-changing moments, of course, are rarely anything of the sort. Political campaigns do not pivot on individual moments or blunders. Fundamentals matter more. And yet the fundamentals are in turn shaped by the accretion of a thousand impressions. At least in part. The campaigning matters too. Especially in a close race.

So this minister – believed, as Iain Martin says, to be a relatively junior Tory – has to be cashiered (and then some) as swiftly as possible. His (or her?) stupidity has badly damaged the Unionist cause. HMS Union is not sunk but she is badly damaged and will not regain full speed for some time.