THE SNP is facing a diplomatic crisis as it comes under pressure to recognise Catalonia's proposed independence referendum.

Party leaders have been urged by long-standing Catalan allies to formally endorse the vote, which is scheduled for this autumn despite being declared unconstitutional by Spain.

But insiders warn that First Minister Nicola Sturgeon will have to show extreme caution to avoid a fall-out with Madrid, which has only just dropped veiled threats to torpedo any independent Scottish membership of the European Union.

The Herald:

The SNP last night appeared to be carving out a carefully balanced stance under which it would congratulate the winners of the vote, should it take place as scheduled on October 1, while ministers repeat a well-rehearsed statement that it was up to Spain and Catalonia to sort out their own constitutional arrangements.

An alliance of Catalan independence supporters secured power last year in parliamentary elections billed as a proxy vote on independence.

They have ever since been at loggerheads with a hardline unionist government in Madrid which refuses to countenance a Scottish-style mutually agreed independence referendum. Their proposed unilateral referendum is expected to be a flashpoint in the stand-off between the two Iberian nations with both Madrid and Barcelona lobbying hard behind the scenes for diplomatic support.

The Herald:

Veteran Catalan 'independentista' Josep-Maria Terricabras said Scotland was one of a handful of nations he thought would be first to recognise the referendum.

Speaking to The Herald at the European Parliament in Strasbourg, he said: "If the referendum is done as we expect it will be done, in a proper way, according to the legal procedures, I would expect the Scottish Parliament to accept it."

Mr Terricabras, a respected philosophy professor who represents the SNP's formal allies Esquerra Republicana, admits other nations will not rush to recognise a result.

He said: "Up to now I don't think the international community has shown great hostility. The Spanish government has tried to get some declarations but it has not succeeded. If we have a good election and a good result, not just 51-49, this will be accepted by the international community. Not at once, suddenly, by all of them. But some countries will be prepared to accept that. If you break the unanimity you have broken the hostility."

Mr Terricabras is hoping Baltic and Scandinavian nations - as well as Scotland - would recognise a Yes victory, which is suggested, narrowly, by most recent polls. The MEP himself "thinks and desires" that the result could be 60-40 in favour of independence on a strong turnout.

Catalonia watcher Michael Keating, however, warns of an "explosive" situation in Iberia and said he would expect other European states - and the SNP - to tread carefully.

Prof Keating, of Aberdeen University, said: "I would expect the Scottish Government to be very cautious. The SNP does not want to provoke Spain."

The Herald:

SNP insiders suggest that one of the party's backbenchers could lodge a motion at Holyrood backing a Yes victory in Catalonia and that this would allow Green and SNP members to vent their support while not compromising the government. Prof Keating said: "I think that is predictable but I don't think it would influence anybody." Such a motion would not be whipped. It could therefore be welcomed by Catalan 'independentistes' while ignored by Spanish unionists.

The Herald asked the SNP if it would recognise a win for Catalan independence supporters. A spokesman said that they would "congratulate" their allies before adding a stock response: "These are matters for the people and the governments of Catalonia and Spain. The constitutional arrangements in Scotland and the UK are clearly different, as has been widely acknowledged. "

Catalan figures have suggested that they could unilaterally declare independence shortly after a Yes vote. President Carles Puigdemont on Friday claimed the Catalan government, the Generalitat, was ready to collect all state taxes, the ultimate signal of sovereignty.

However, senior Spanish figures have cast doubt on both this and the ability of the Generalitat to secure global support. José Manuel García-Margallo, until last year Spain's foreign minister, told Spain's hardline unionist ABC that Catalonia risked becoming like one of the largely unrecognised states, such as Western Sahara or Southern Ossetia. He said: "Without recognition [Catalonia] runs the risk of falling in to legal limbo."