Catalan President Artur Mas has been summoned to court for holding what prosecutors say was illegal independence referendum last year.

Just two days after storming to victory in regional elections, Mr Mas was told he will face formal charges of civil disobedience and "usurpation" of powers.

In a propaganda coup for his movement, his court case on October 15 will coincide with the 75th anniversary of the execution of a previous Catalan president, Lluis Companys, in 1940, by the regime of fascist dictator Francisco Franco.

Catalan "independentistes" immediately seized on the legal action as an example of the legalistic intransigence from Madrid authorities that has done much to spark Mr Mas's victory on Sunday.

However, Spain has stuck rigidly to its constitutional position that any referendum on independence would be illegal.

Mr Mas's previous administration has tried to carry out a Scottish-style vote in November 9, 2014.

This was blocked by the Constitutional Court of Spain. So instead he held what has been called a "public consultation" or "consulta", dubbed 9-N because of its date.

Observers judged it to be little more than one of a succession of impressive but ultimately purely symbolic mass protests.

Its results did not reflect the mixed opinion in Catalonia, with unionists largely staying away.

However, more than 2.3 million people voted in the action with 80 per cent of them backing independence from Spain.

Mr Mas former vice president Joana Ortega and Irene Rigau, his education minister, have also been summoned to court.

The investigation in to their referendum began last December. Madrid reports suggested that the timing of the courts summons - two days after Sunday's election - was co-incidental.

The very date, however, has huge resonance for Catalan nationalists.

The court concerned is the High Court of Catalonia. However, his prosecutors are Spanish.

Spanish Prime Minister Mariano Rajoy, facing Spain-wide elections just before Christmas, has refused to negotiate with Mr Mas.

The SNP Government in Scotland has offered its assistance - and experience of last year's legally-binding Scottish referendum - to both sides.

However, on Monday, Mr Rajoy said there could be no dialogue to discuss the end of "the unity of Spain".

Mr Mas and his allies won a majority of seats in the Catalan parliament and 48 per cent of the vote. His unionist rivals achieved 39 per cent of the vote with ambivalent parties taking the rest. Both pro and anti-independence groups claimed a moral victory.