Astonishing rooftop views as hundreds of thousands fill Barcelona roads on Catalonia Day

Hundreds of thousands of Catalan separatists have joined a rally in Barcelona demanding independence from Spain.

The march is taking place in connection with the celebrations of the "La Diada" holiday on Tuesday.

It comes nearly a year after an illegal referendum on secession held by Catalan authorities led to an ineffective independence declaration that received no international recognition.

"We have come here today to demand once again freedom for Catalonia," said 57-year-old Lourdes Casajus, who came from her home in the Catalan heartland to join the separatist rally.

Independence demonstrators march during the Catalan National Day in Barcelona. Credit: AP

"Last October 1 we voted in a referendum and the majority for independence wasn’t respected. This September 11 we demand that all the politicians, both from there and ours here, respect the people’s will," Casajus added.

Catalan separatist leaders and activists who pushed the referendum, defying Spain’s constitutional protection of territorial integrity, are either awaiting trial in prison or fled the country.

Quim Torra, the Catalan regional president, said while maintaining his pledge to see through the breakaway bid, his immediate focus was on putting pressure on the courts ahead of the trials of the movement’s jailed leaders.

Quim Torra walks by a Catalan police honour guard in Barcelona. Credit: AP

His goal is to whip up support for public showings of strength on October 1, the anniversary of the referendum that was met by a police crackdown, the failed declaration of independence on October 27, and the imminent start of the trials.

"In the coming weeks we are going to put all our efforts into denouncing" the situation of the jailed separatists, Mr Torra said.

He said he would not go as far as throwing open the cells of the secessionists, who are being held in Catalan prisons run by his administration.

Some within the secessionist movement want Mr Torra’s government to immediately try again to unilaterally break with Spain.

An anti-independence protest in Barcelona, held on Sunday. Credit: AP

Mr Torra, who rose to power after secessionist parties won a regional election, has met Spanish prime minister Pedro Sanchez and is planning a second meeting.

He wants Spain’s new centre-left national government to agree to a binding independence referendum, while Mr Sanchez will only offer a vote on increasing Catalonia’s already considerable degree of self-rule.

Polls and official election results indicate roughly half of Catalonia’s 7.5 million residents are against severing century-old ties with the rest of Spain.