THE language of politics can be highly instructive and deeply revealing as to the motives and priorities of individuals, parties and campaigns.

As such, the language of the No campaign on the issue of what currency an independent Scotland should use is perhaps more revealing than they had ever intended.

Their obsession with a "Plan B" says it all. Implicit in that formulation is settling for what is second-best, and in this case what would be second-best for Scotland.

Having spent my entire political career fighting for what I regard as being in the best interests of Scotland, I am not going to settle for second-best on currency or anything else.

I took the opportunity at Holyrood on Thursday to make one thing abundantly clear - it's our pound and we are keeping it.

There is literally nothing anyone can do to stop an independent Scotland using sterling, which is an internationally tradeable currency.

The Scottish Government commissioned a group of eminent economists, with two Nobel laureates - Joseph Stiglitz and James Mirrlees - among their number, to look at the currency options for an independent Scotland, and their detailed report was published last year.

It concluded that retaining sterling in a formal currency union is the best option for Scotland. It is also the best option economically for the rest of the UK.

As such, the No campaign's tactic of saying no to a currency union makes absolutely no economic sense.

But it also makes no political sense, and is a tactic that is a deeply dangerous one for them.

They are playing with fire, and they risk neglecting a cardinal rule of political campaigning, namely not learning your lesson from past mistakes.

When George Osborne came north earlier this year to deliver his "sermon on the pound", the effect on the independence debate was instantaneous. Because, doubtless to the consternation of the Chancellor and his senior mandarins in the Treasury, far from recoiling in fear, the Scottish electorate decided to stand up to the bullying diktat from Westminster, and support for independence in the polls shot forwards.

If the No campaign think that spending the rest of this campaign telling ordinary people in Scotland that they have zero entitlement to a currency that is already theirs and which they can't be stopped from using in any case, they will pay a heavy price.

The Fiscal Commission Working Group's report last year listed several viable currency options for an independent Scotland, including our own currency, either fixed or floating. They also examined the euro - which they and we don't support. They also pointed out that no one could stop Scotland using the pound - our own currency.

But their conclusion - that a formal sterling union is the best option - is backed by sound economic considerations. It makes sense to continue to use the pound given the trading patterns between Scotland and the rest of the UK and the fact it will mean no transaction costs added to cross-border business flows - and Ed Miliband has now admitted that these costs to businesses in England would run to "hundreds of millions" of pounds a year.

And that brings us to the other key reason that a refusal to a currency union makes no political or economic sense from a Westminster point of view.

It is simply impossible for the Westminster establishment to follow through on their campaign rhetoric about blocking Scots using the pound. They can however deny Scotland continued use of the Bank of England, which is a shared asset that Scottish taxpayers have contributed to since it was nationalised in 1946.

The Bank of England itself holds the title to over a quarter of the UK's entire national debt of around £1.3 trillion. And it is all that debt which Westminster would be agreeing to take on board in its entirety if Scotland was denied continued use of the central bank.

Assets and liabilities go hand in hand, and no one would expect Scotland to pick up a share of the debt if we were being denied a share of the assets.

In any case, the UK Treasury has already accepted that they are legally liable for all UK debt accrued up to the point of independence, something they made explicitly clear in a statement to the markets on January 13 this year.

January 13 is proving unlucky for the Unionist No coalition. We take the fair, reasonable and responsible position that an independent Scotland should agree to pay our fair share by servicing that debt.

Voters across the UK would look askance at any Westminster politician campaigning on a platform to reject a currency union, given that it would mean rejecting Scotland's offer to contribute debt interest payments of up to £5 billion a year and instead adding that to the debt burden for the rest of the UK's taxpayers, while an independent Scotland starts life debt-free and Scot free.

It's at that point that Ed Miliband's hasty gambit to include a block on Scotland's continued use of the pound in Labour's next Westminster manifesto would start to look less like a cunning electoral plan and more like an self-inflicted double whammy.

He would be simultaneously saying to Scots: "I will defy the sovereign wish of the people in a referendum", and to the English: "Pay up to stop the Scots sharing the central bank".

It's for reasons like these that Westminster's pronouncements on the pound are more kamikaze than convincing, why an unnamed senior UK minister has admitted "of course" there will be a currency union after a Yes vote and why even Alistair Darling believed only last year that it was "logical" and "desirable".

Therefore it is Scotland's pound.

And we are keeping it, come what may.

On Thursday the Scottish Parliament unanimously accepted in 20 seconds what it took 20 questions to prise out of Alistair Darling last Tuesday - that Scotland could be a successful independent country.

On 18 September we should make that a reality.