THE sheer scale of the SNP's surge since the referendum may be horrifying British unionists.

But it seems to be making their Spanish counterparts just a little bit smug.

Opponents of independence for Catalonia, using the full weight of the Spanish state and judiciary, blocked a Scottish-style vote.

Now the rise of rise of Scottish nationalism before and after September's plebiscite has convinced them that this was the right thing to do.

"Cameron's strategy is failing," declared Cronica Global, a staunchly unionist news site in Barcelona. "The independence referendum has not pacified Scottish nationalists."

True, without some kind of unifying, formal referendum, the national movement in Catalonia, always more divided than Scotland's, has drifted.

Polls, for the first time since 2011, are showing a narrow majority of Catalans favouring the status quo or federalism over a notion of "independence" that was never quite as clearly defined as in Scotland.

The lesson for Spanish unionists? Don't have a vote: it only encourages them.

Michael Keating, of the Centre on Constitutional Change, senses that that some Spanish and Catalan unionists feel vindicated.

The veteran watcher of all things Iberian said: "Since support for independence is going off the boil in Catalonia but heating up here, Spanish unionists are able to draw different lessons.

"They think 'We were right not to have a vote' and 'We should hold our nerve and this thing will go away.'"

Scotland's vote made David Cameron an unlikely hero of independence movements around the world.

Catalan nationalists, for example, rarely lost an opportunity to contrast the Tory prime minister's good old English 'fair play' with what they saw as a Neo-Franquista hardline from Madrid.

Fierce opponents of Tamil independence, however, saw our big vote as a scheme worthy only of "mad dogs and Englishmen".

So what's better for unionists? To vote or not to vote? Well, that depends.

Scotland's Better Together leaders hoped the referendum would park independence for a generation.

When the vote was was first agreed one senior unionist told me such a "victory" would require a No majority of 3-1.

A leading federalist - or unionist - in Quebec made the same point: without an overwhelming No, nationalism, he said, "will never go away".

But Prof Keating reckons the Catalan issue won't go away either, even without a vote.

Scottish independence supporters, Prof Keating argued, have forged a "critical synthesis with the social democratic mainstream" and a social movement against austerity.

In contrast, their Catalan allies, already divided, are up against protest parties, such as the anti-austerity Podemos and Cuidadanos, right-wing populists born out of an anti-nationalist backlash in Catalonia.

So are Spanish unionists right to crow? No, says Prof Keating.

"The unionists in Catalonia are scenting victory - but probably wrongly. "The same thing happened in Scotland in the 1980s - after the 1979 referendum - when people thought Scottish nationalism had gone away.

"Well, the issue is not going to go away in Catalonia. It is going to rankle. But we may be going through a post-79 moment in Spain."