Scotland is about to become "one of the most powerful devolved parliaments in the world".

That, at least, is the boast of David Cameron. And, brace yourselves, you're going to hear it endlessly over the next couple of months.

Why? Because such dull sloganeering is one of the prices we are all paying for the new powers released by this week's big financial deal between Edinburgh and London.

But is the prime minister right? Probably not, no.

The world, after all, is a big, big place and is dotted with semi-independent statelets that pack way more power over their own affairs than Scotland. One, the Faroe Islands, is just off our shores and pictured below.

Our northern neighbours - who know us so well they use our political jargon - reckon they have the "Devo Max" we have never quite been offered.

The Faroese, just as one example, can make sovereign decisions such as whether to be in the European Union or not. Scotland can't.

So it's pretty tempting just to file Cameron's boast under "stupid noises politicians make" and forget about it.

But I don't think we should. We really should be wondering where we rank on a notional league table of world autonomy.

Because doing so is a fantastic way of thinking about just how much power and influence we want in Scotland - and about exactly what constitutes power and influence for a stateless nation or region.

Some academics have had a bash at putting together a league table, the Regional Autonomy Index. Scotland, needless to say, isn't at the top. Such honours go to places like Spain's Basque Country and Srpska Republika, the Serb-ruled half of divided Bosnia.

Picture: Basque Country's classiest resort at San Sebastian

The official Tory line, for what it is worth, seems to be based on Holyrood research showing Scotland ranking above US states or German lander but behind Canadian provinces or Swiss cantons.

Such rankings are based on how much tax is raised and spent in Scotland compared with other sub-state regions.

I'm not convinced that's the best measure. Why? Because power and influence cuts two ways. First is how much sway a central government has over its region. Second is how much sway a region has over its central authority.

Academics call the former "self-rule" and the latter "shared rule".

Nicola McEwen, pictured below, is a professor of territorial politics at Edinburgh University. I asked her whether Scotland was one of the world's most powerful devolved parliaments. "In terms of self-rule, yes," she said. "In terms of influence over the centre, no."

And here we get to the heart of the matter: Britain, unlike Canada or Russia or America or Germany, isn't a federation.

So it doesn't make a whole lot of sense to compare Scotland with, say the tiny US state of Rhode Island, which has the same number of votes in the federal Senate as mighty California.

There was another political boast just ahead of the independence referendum.

Scotland, former prime minister Gordon Brown said, would be "as close to federalism as you can have in a nation where one part forms 85 per cent of the population." He, like Mr Cameron, was wrong.

More background: Federalism is hard to deliver in states with one nation or region that is bigger than the others. David Leask on Spain's troubled federalists.

More Background: Columnist David Torrance on Gordon Brown's federalism