When all three parties, and Treasury mandarins, agree...

My great-aunt, who was a foreign correspondent in 1938 and therefore an expert on rising nationalism, used to say that Liberalism and Nationalism were opposite ends of the political scale - in some ways, far more fundamentally opposed than simple left and right.

But there are two exceptions to that law.  One is that, in the UK, British Liberals have traditionally turned a blind eye to the limitations of Irish nationalism.  They may not have turned a blind eye to its dark side, but they were allies of the Irish Nationalists in Parliament for most of the second half of the nineteenth century.

Because they also believed in self-determination.  They were just sceptical about nation states, and quite rightly.

The other exception I've just noticed.  I am a loyal member of the Liberal Democrats, and have been since 1979.  I believe their work in the coalition is difficult but vital, and courageous.  But when their leaders, and the Labour spokesman and George Osborne, all line up at the same press conference - and when senior civil servants support them - well, even I begin to get a bit suspicious.

I am not and never will be a nationalist, Scottish, English or any other kind - but the sheer negativity poured on the idea of Scottish independence has made me a good deal more supportive of it.

And, by the way, whose bright idea was it to use George Osborne as a paragon of avuncular trustworthiness?

Of course the Scots will be able to use the pound, or a currency tied to the pound, just as - in effect - most of Latin America until recently used the US dollar.  They will have no say in its management without the agreement which Osborne ruled out, but they have little say as it is.

My solution would be for Scotland to create the climate for a multiple currency state, which is the direction we are all heading anyway.  They would use the pound for most major transactions, the euro for cross-border ones outside Great Britain, and a Scottish or other city currencies for local spending.

This gets more interesting when you think what kind of design the other currencies might have.  Personally, I would propose a Scottish pound as a store of value currency, but with local city currencies - probably with a negative interest rate to encourage non-inflationary spending, rather as proposed by Senator Bankhead in the USA in 1933.

This design would allow Scotland to leapfrog the glacial pace of the development of currencies in most of the world.

Because, behind this debate there is something else.  It isn't really about national sovereignty because Scotland would be in the EU and there would have to be co-ordinating bodies for these islands.  It isn't so much national sovereingty as re-arranged sovereignty that Scotland would get if it voted for independence.

Independence itself is not possible, nor actually desirable, for any nation these days.

No, what is at stake here is the question of whether a small nation can thrive economically.  Evidence from Scandinavia suggests that it could.  The success of city states like Hong Kong or Singapore suggest that there is nothing absolute about scale when it comes to success.

But what is absolutely necessary is some measure of currency independence.  And some imagination.

What Scotland has gained from the independence debate, it seems to me - despite all the hot air - is the ability to bring together imaginative people and re-think the future, in a range of ways.

Every time I read another forward-looking, positive report from the Yes camp, on public services or social care - imaginative, hopeful, progressive and practical - I wish that England would have the same opportunity.

Sitting on the Lib Dem public services commission, as I do, is very interesting - but it isn't quite enough.