The rally will start with supporters gathering outside the Australian High Commission on the Strand before marching to Parliament Square. Assange, 48, is being held in Belmarsh Prison in south east London as he awaits the start of next week’s full extradition hearing.

He is expected to receive a visit from his father John Shipton and former Greek finance minister Yanis Varoufakis on Sunday before the hearing starts.

Assange is wanted in the US on 18 charges over the pPink Floyd star Roger Waters will headline a rally in central London today protesting the extradition and demanding the release of Wikileaks founder Julian Assange.publication of US cables a decade ago. If found guilty he could face a 175-year prison sentence.

Speaking on Friday to promote the protest, Waters dismissed the charges against Assange as “nonsense” and claimed he faced a “kangaroo court”.

“He has committed no crime, he published something, he’s a journalist, he did what journalists are supposed to do. There was no threat to national security,” Waters said.

“It looks as if the powers that be have every intention of submitting to the demands of the United States government to have him extradited to the US so they can lock him up until he is dead.”

Assange has been held on remand in Belmarsh since last September after serving a 50-week jail sentence for breaching bail conditions while staying in the Ecuadorian embassy in London.

He entered the building in 2012 to avoid extradition to Sweden over sex offence allegations, which he has always denied and were subsequently dropped.

Waters suggested Assange should not be held for a “minor bail infringement”.

Asked who he believed was behind Assange’s imprisonment, he said: “The ruling class, the powers that be… the corporate world, the rich people, the people who run everything, the people who tell (prime minister) Boris Johnson and (US President) Donald Trump what to do. Those people.“

“I’m not suggesting there are men in hoods and secret societies but we all see what’s happening.”

Speaking to the press near Battersea Power Station in south London, Waters posed for photographs next to a version the inflatable pig balloon that featured on the cover of Pink Floyd’s 1977 album Animals.

The original blow-up animal was famously flown above the power station in London in 1976, but caused disruption to flights from Heathrow Airport when it broke free and blew off into the sky.

It was later recovered from a field in Kent.

Waters previously called for the release of Assange during a rally outside the Home Office in central London in September, when he played his former band’s hit track Wish You Were Here from a makeshift stage.