Even Sparta’s mythical iron-bar currency – specifically designed, so legend had it, to shackle the economy by being too heavy to buy or trade anything – was marginally better, in Alistair Darling’s view, than anything an independent Scotland might be able to use for money, all of which will lead to inevitable doom.

Because Scotland, as all good unionists know, is the only country in world history for which there is no currency option that will work at all.

Currency is one of those issues – the wicked issues, as commentator James Maxwell called them – which are inherently uncertain, on which there can be no definitive, pre-referendum answer unless it’s prenegotiated and we’re tied into it. The EU is another. They are subject both to negotiation (and to the democratic will of the Scottish people), and to uncontrollable influences outside Scotland.

It’s reasonable to assume, however, that negotiations will happen in a spirit of magnanimity. People will be looking for the best solution for themselves nationally and for business, with the minimum of disruption. Staying in the EU and sticking with Sterling are, in that respect, clearly the common-sense options.

So lets look at it another way: let’s say the Scottish government wasn’t offering these. Imagine for a moment the White Paper had put forward the proposal to pull out of the EU, and leaving Sterling to start up a new currency. Those positions would have been attacked mercilessly by the No camp and the media, for all the obvious reasons.

Accusations of beggar-thy-neighbour policies towards the rUK would have been thrown at them. Not just independence, angry No campaigners would say, but a spiteful one with no attempt at retaining the social bonds of union. Damaging trade, increasing the rUK’s deficit and foreign currency issues, weakening Sterling, unsettling the markets. The business community would have screamed in horror even more than it already is.

So it’s probably worth remembering that there’s no possible argument for any sort of meaningful change that wouldn’t cause a panic from the people who made all the same dire warnings about devolution, and treating their doom-laden predictions accordingly.

The independence movement in Scotland is not a new one. It’s an ancient, battle-scarred and time-tested one which has prevailed patiently through long campaigns, and has already seen the worst the British state can throw at it. The tactics on the unionist side, being almost entirely reheated from 1979/97, are wholly predictable.

This is perhaps why the SNP government didn’t put forward its currency proposals off its own bat, but instead assembled the Fiscal Commission working group. A heavyweight collection of economic experts including two Nobel Prize winners, it produced an in-depth analysis which considered all options and set out why, in its opinion, a currency union was the best way forward for Scotland and the rUK alike.

Now, if polls are correct, many people in Scotland would still prefer “devo max” to full independence. So it seems reasonable to assume that they’re already happy to cede the amount of sovereignty Westminster would demand for a currency union, and that this may explain their reluctance to panic in the face of the united front from the UK’s present and would-be Chancellors as they bizarrely insist that Scots should vote No because the independence on offer won’t be independent enough.

The Westminster parties did have another option. They could have agreed in principle and opened pre-negotiations. A joint statement could have been produced saying “This is what is proposed by the Scottish Government, and these are the broad terms on which rUK would agree to it. The finer points will be negotiated after a yes vote, and both positions will be ratified by the elections of 2015 and 2016.”

That would have given Westminster a strong negotiating hand. It would have left the option open, had there been significant political pressure against, for either rUK or Scotland to back out after a Yes vote, but it would have been seen to have played fair.

Instead, the No parties opted for the much cruder tactic: use currency as a club to beat the dastardly Nats with. But the danger with swinging a club instead of talking is that if you’re not careful, the club can be snatched away and used against you.

Keeping the pound is not something that either the Unionists or Westminster have any veto over. Scotland can use the pound without a formal currency union for as long as it wishes. Ireland used it that way for 58 years. A succession of independent experts have pointed this out, and a still-unidentified UK government minister let the cat well and truly out of the bag last month.

Not only did the tactic fail in its initial goal of sending terrified Scots flocking towards the No camp, it then backfired horribly. First the people of Scotland were given the impression they were being threatened and bullied (rarely a vote-winner), and then it rapidly became clear they were being lied to as well, in a double-whammy of PR disaster for Alistair Darling and his not-very-merry men.

Meanwhile, the other options remain open. On the Andrew Marr Show recently, the host kept badgering Salmond to make a case against Scotland having its own currency. Wisely, Salmond didn’t bite and made no such case against a Scots pound. The Fiscal Commission, after all, had concluded that “Scotland could choose any of these options and be a successful independent country”.

There can be, and will be, no bar on Scotland using the pound should it choose independence this September. The only people who will ultimately decide what Scotland’s currency will be in 2016 and beyond will be the electorate. Should they, of course, have chosen to give themselves the power to do so.