MADRID (Reuters) - Catalonia’s Supreme Court indicted the acting head of the Catalan regional government on Tuesday after he pushed ahead with a referendum on independence from Spain last year despite such a vote being ruled unconstitutional by the courts.

Artur Mas, the acting head of Catalonia's regional government, speaks during a meeting at the regional government headquarters in Barcelona, Spain, September 29, 2015. REUTERS/Stringer

The preliminary charges of disobedience, abuse of authority and usurping authority are levelled at Artur Mas, the most visible face of Catalan separatist aspirations, just two days after his party won a regional election.

Secessionist parties on Sunday secured an absolute majority in the regional parliament, although they won 48 percent of the votes cast.

Mas will testify in court in October for pressing on with a non-binding referendum on independence last November after it was suspended by the Constitutional Court, backed by Spain’s national government.

Prime Minister Mariano Rajoy’s tactic over years of growing support for Catalan independence has been to stick doggedly to the letter of the law.

With a general election set for December, Rajoy has ruled out the possibility of a referendum on the issue, despite polls which show most Catalans are in favour of having the choice.

He argues, supported by a vast majority of Spaniards, that one part of Spain cannot decide what happens to the whole.

Mas said when the proxy referendum took place on November 9 2014 that he would not be intimidated by the legal tactics of the Madrid government. He said he hoped no legal action would be taken.

After the Catalan elections brought tensions to a new head, most political parties are now offering the chance of dialogue and do not rule out a potential change in Catalan financing.

Rajoy’s mantra on maintaining the status quo saw his People’s Party garner its worst result in a Catalan election in more than 20 years.