The speaker of the Catalan parliament has insisted that the deposed regional president, Carles Puigdemont, remains the only candidate to form a new government, as he renewed his call for a negotiated political solution to the independence crisis.

Roger Torrent, who became speaker following December’s snap elections, told the Guardian that while he hoped for dialogue with the Spanish state, Catalonia urgently needed a new government to bring an end to direct rule from Madrid.

The region has been under the control of the Spanish government since the end of October, when Spain’s prime minister, Mariano Rajoy, responded to Puigdemont’s unilateral push for independence by using article 155 of the constitution to sack his secessionist administration and call fresh elections.

“We need an investiture as soon as possible so we can have a government that’s effective and that can go about eliminating article 155 from the political landscape of Catalonia,” said Torrent.

“Carles Puigdemont is the only candidate. He’s been proposed by a parliamentary majority, and in a parliamentary democracy, the candidate who’s put up for an investiture debate is the one who commands the support of the majority of the MPs in the chamber.”

However, Puigdemont’s candidacy is deeply problematic. He has been in self-imposed exile in Brussels for more than three months and faces arrest on possible charges of sedition, rebellion and misuse of public funds the moment he returns to Spain.

Carles Puigdemont, right, talks to the press in Leuven, Belgium, on 6 February – 100 days into his self-imposed exile. Photograph: Thierry Roge/AFP/Getty Images

The Spanish government had flatly refused to countenance his return to office, suggesting instead that the Catalan parliament put forward a “clean candidate”. At the end of January, Torrent postponed a planned session to invest Puigdemont, saying he did not have the necessary legal guarantees to proceed.

Asked whether it would be quicker and easier to end direct rule by choosing a different candidate, Torrent said it was not his job as speaker to decide who should run for the presidency. Anyway, he added, Catalan voters had made their preference clear in the December poll, in which the pro-independence parties retained their parliamentary majority.

“The message from the ballot boxes on 21 December was: ‘We want to get our institutions back and we want to ditch 155’,” he said. “I think that’s obviously what a parliamentary majority is proposing. It’s not the Catalan parliament that has the problem here, it’s the Spanish government. What’s it going to do? Ignore the results of 21 December?”

Torrent would not be drawn on reports that Puigdemont – who has vowed to press on with the independence process – was planning to assume a symbolic role from Brussels or that his party, Together for Catalonia, was now considering whether to propose a different candidate.

But he did say that his party, the Catalan Republican Left, had sought negotiations with the Spanish government.

“We’ve always proposed dialogue,” he said. “The first thing I did when I took office was send a letter to Prime Minister Rajoy, asking for him to sit down and talk so we could look for a political solution to the problem.” The offer, he said, remained open.

Torrent, who was speaking after visiting the four Catalan leaders currently in Spanish prisons, accused the Madrid government of trying to turn a political issue into a judicial matter.

“They’re political prisoners; they’re there because of an idea,” he said. “If anyone says they’re not political prisoners, I suggest they read the judge’s rulings. They will see that, basically, the court is getting people to renounce their political ideas. That makes them political prisoners.”

While he understood the EU’s reluctance to be drawn into the Catalan question, Torrent said he expected it to “help us to defend democratic principles and … not allow there to be political prisoners in 21st century Europe. I think that’s the least we can ask of them”.