George Osborne may not want a monetary union with an independent Scotland.

But the Chancellor last week certainly found a common currency with some of the world's other unionists.

His refusal to negotiate on a shared pound - although quickly labelled a "threat" by many in the overseas media - has been seized upon by his Conservative allies in Spain and Canada.

Osborne's gambit, after all, slots perfectly in to well-rehearsed currency arguments in both states. Why? Because the SNP isn't the only supposed separatist group which favours monetary continuity after independence.

For example, Catalan independentistas, among the biggest Europhiles on the continent, want to keep the Euro. And Quebec's sovereigntists have, in recent decades at least, embraced the Canadian dollar as their own.

Let's take the Spanish case first.

"Catalunya, like Scotland, will have to find its own currency," declared Andalusian daily Diario de Sevilla in a headline after the chancellor's speech in Edinburgh.

Catalans, the staunchly unionist paper reported, "would go through something similar to Scotland" before explaining, not quite accurately, that Osborne had warned Scots that if they go independent they "would not be able to use Sterling".

The unionist pitch in both Britain and Spain is the essentially the same: that independence threatens the money in your pocket.

But there is - for me - an amusing paradox between the currency warnings in London and Madrid.

Some UK unionists still argue that Scots may be forced to use the euro as their price for rejoining the European Union.

While Spanish unionists claim Catalans may be forced to quit the same currency, as their price for leaving the same bloc.

"An independent Catalunya would leave the EU and the Eurozone and, therefore, would not be able to use the common currency as its national money," reported Diario de Sevilla. It then cited remarks from Joaquín Almunia, the (Spanish) vice-president of the European Commission that any country that left a EU member state "would have to knock on the door" to get back in the bloc.

This was, in yet another outing for the claim, repeated this weekend by European Commission President Jose Barroso.

Both Scotland and Catalunya, in the scenario painted by anti-independence leaders, would be out of the EU. They might still use, respectively Sterling and the Euro, but only on the kind of terms Ecuadorians use the US dollar, with no influence over interest rates and no shared regulatory institutions.

Is this likely? No, say independence supporters in both Edinburgh and Barcelona. Because it simply wouldn't be in anyone's interests.

That brings me to Quebec. There was no added confusion of EU membership, of course, when Francophone sovereigntists last tried to break away from Canada in 1995. But there was debate on a currency union. Nationalists, to use our terminology, wanted to keep the Canadian dollar.

Their unionist or Federalist critics trashed the proposal, which was made just after the quick collapse of a currency union between the newly separate Czech and Slovak republics.

Scroll forward two decades and Anglophone Canadians see one of their own, Bank of England Governor Mark Carney, walk in to a similar dispute between London and Edinburgh.

Carney's conclusions last month - that Scotland would have to cede sovereignty to share a currency, at least formally - were the subject of fierce enough polemics in Scotland.

Nationalists thought what he said was obvious, an acknowledgment that there is no absolute sovereignty for any state, large or small.

Unionists thought the Canadian central banker had killed a currency union, or, at the very least, prepared it for a formal execution by Osborne.

André Pratte, editor-in-chief of Montreal's La Presse, was more interested in what Carney's warnings on ceded sovereignty meant for his province's own "sovereigntists".

Carney's argument, the prominent Francophone federalist wrote last month, "strikes at the heart of Quebec independence: the idea that an independent Quebec would have all the tools to manage its economy".

Quebec, the journalist explained, would have to negotiate a new monetary union with Canada. He concluded: "As Mr. Carney points out, a monetary union is impossible without common institutions. There's no guarantee that such a deal would be more advantageous for Quebec that the system in place today. The opposite is more likely."

Toronto's Globe and Mail last week said Osborne's warning - backed by his Labour and Liberal Democrat counterparts - explained why Carney "felt comfortable weighing into a private British quarrel with his doubts about currency union".

The firmly federalist paper, meanwhile, scoffed at the very idea that "so much of the argument now seems to be turning on the currency".

Writer Carl Mortished said: "Over the past century, countless nations have fought for independence, but one cannot think of any movement which lost its way over an argument about monetary policy.

"Could it be that in a materialistic and technocratic world, the currency and its intrinsic value has come to mean as much to people as the language they speak, their cultural habits and the political institutions by which they govern themselves?

"Or, could it simply mean that the Scottish people are quite happy, broadly speaking, with the way things are and simply want to know whether independence will add up to more or less porridge?"

Let's ignore the porridge jibe. But Canadians with longer memories stress the early part of the 1995 referendum debate was also, initially at least, bogged down in similarly prosaic disputes. Yet the vote ended in a near tie after the "Oui" campaign was effectively taken over by the charismatic Lucien Bouchard and somehow made up a huge deficit in the polls. Canada almost ended in 1995 - but not, as Mortished would no doubt say, because of pointy-headed arguments about the merits of monetary unions.

There is nothing new, meanwhile, in "separatists" sticking with the same money, at least for a time, after creating a breakaway state. Norway did so1905. Ireland in 1928. So too did many of France's former colonies. But, as Canadians know, there is also nothing new about sowing doubts about the certainty of such currency unions.