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.

As the minister said:

“You simply cannot imagine Westminster abandoning the people of Scotland. Saying no to a currency union is obviously a vital part of the no campaign. But everything would change in the negotiations if there were a yes vote.”

What were they thinking? If ever you needed reminding politicians speak to journalists much more often than they should (and hurrah for that) this is it. There’s no possible benefit to be drawn from these remarks, no useful cause advanced, no point to them whatsoever. Save, I suppose, the satisfactions of ego.

It is not just about the currency, you see. These remarks harm every single claim made by Unionists and the Better Together campaign. This minister is making claims he cannot honour of course – that one minister says of course a currency union could be agreed scarcely means it would be – but that is not the real damage.

We will hear these lines a thousand times before polling day. What a gift for the nationalists! See: even government ministers don’t believe the line being sold by George Osborne and Danny Alexander. The suggestion there’d be no currency union is a campaign ploy. Froth. Bluster. Not to be taken seriously. Dinnae fash, they’ll come to their senses. Why, look, they even admit it all themselves.

And if they will “lie” about a currency union might they be lying about everything else too? One thing in public, another in private. That’s the Unionist hypocrisy for you. They’re not being straight with you. They can’t help it, it’s just their nature. But you can’t trust the Tory-Labour-Liberal Alliance. Only the SNP will stand up for Scotland; only the Yes campaign will tell you the real truth.

Nonsense, naturally, but the sort of nonsense that can be persuasive. In Washington, it’s said that a gaffe is when a politician accidentally blurts out the truth. From the nationalist perspective, this minister has committed an almighty gaffe.

Osborne and his colleagues dispute this, of course. The official line – no currency union, don’t even think about it pal – still stands but it offers less shelter or protection that it did 48 hours ago.

This need not be a fatal blunder but it is hard to avoid the thought that this is a black, bleak moment for Unionists. It is tough to win a race when one of your team-mates has blown your foot off.

As for the Nats: they have every right to be cock-a-hoop. We told you so. Who can you trust, baby? Precisely.

Sometimes you need to shoot a politician on Palace Green, just to encourage the others and remind them of their duty and loyalties. This is one such moment even though the damage is done and cannot be repaired for some time.

PS From Fraser - Alex’s blog headline is a nod to the description of Admiral Byng, who was executed as a warning to British sailors not to retreat from the enemy. This tactic was admired by Damian McBride, who adopted an  “Admiral Byng approach to leaks.” Here he is. A reminder of what we’re not missing:-

If anything did appear in the papers that was not from X, Y or Z, I would instantly name a culprit. I’d try and choose someone who was a decent suspect, but their guilt didn’t really matter – it was the assertion of their guilt that mattered. They would be cut out of meetings, removed from the circulation list for emails, and wherever they walked in the Treasury, people would mutter about their demise. The effect of this was to make the actual guilty party feel guilty as hell, and put the fear of God into everyone else in the Treasury about doing any leaking themselves. As for the poor Admiral Byngs, they’d usually recover after a while, and some of them were probably guilty anyway.

Tags: Better Together, british politics, currency union, Gaffe, Scotland, Scottish independence, sterling, Tories, Unionism, Unionists