WikiLeaks founder Julian Assange has appeared in the dock at the Old Bailey in the latest round of his fight against extradition to the US.

The 49-year-old, who has been in high-security Belmarsh Prison for 16 months, is wanted over the publication of hundreds of thousands of classified documents in 2010 and 2011.

Assange stood in the dock, inside the Old Bailey’s Court 10 on Monday morning, clean shaven with spectacles perched in his short cropped hair, wearing a smart dark suit, maroon tie and white shirt.

The court heard he has been formally arrested in relation to a new warrant after a fresh indictment was earlier lodged in the US, superseding the previous one.

Assange spoke to state he does not consent to extradition after confirming his name and date of birth at the start of the hearing.

He is facing 18 charges – including plotting to hack computers and conspiring to obtain and disclose national defence information.

The allegations include that Assange conspired with army intelligence analyst Chelsea Manning to crack a scrambled password, known as a “hash”, to a classified US Department of Defence computer.

If convicted, he faces a maximum possible penalty of 175 years in jail.

Assange’s supporters have accused the US administration of targeting the Australian national for “political” reasons after WikiLeaks exposed alleged war crimes and human rights abuses.

Dozens of supporters, including his father John Shipton and fashion designer Dame Vivienne Westwood, gathered outside the Old Bailey on Monday, where a small stage has been erected for a planned protest.

Dame Vivienne told the PA news agency: “I’m an activist, I am very frightened, I’ve lost days and years of sleep worrying about Julian Assange.

“Julian Assange is the trigger, he is shining the light on all the corruption in the world.”

She added: “We’ve got to protect human rights, the establishment is corrupt, they will not listen to Julian.”

Demonstrators roared in applause as speeches demanded the Government free Assange, while some banged drums and carried banners.

Mr Shipton described the extradition hearing as an “abuse trial”, adding: “The insistence, the malice that constantly falls like a Niagara upon Julian is just appalling, and indicates to us that the administration of justice here is enfeebled.”

A mobile billboard van drove past featuring a “Don’t extradite Assange. Journalism is not a crime” slogan and a picture of his face.

Assange’s partner Stella Moris, who has two children with him, was in court after visiting Downing Street in a bid to deliver a Reporters Without Borders petition against the extradition, which has been signed by around 80,000 people.

The extradition case, which was delayed due to the coronavirus pandemic, is being heard by District Judge Vanessa Baraitser at the Old Bailey.

Dozens of witnesses are expected to be called to give evidence over four weeks, with the judgment likely to be delivered at a later date.

Assange’s legal team is being spearheaded by Edward Fitzgerald QC, with James Lewis QC acting for the US authorities.

District Judge Vanessa Baraitser said that due to social distancing measures, journalists were attending the Assange extradition hearing in overflow courts, while other people were given permission to join by a remote videolink.

She warned against a repeat of an incident at an earlier hearing in Woolwich Court Court in which a photograph of Assange in the dock was taken and posted on social media, against strict court rules.

Assange has been held on remand in Belmarsh prison since last September after serving a 50-week jail sentence for breaching his bail conditions while he was in the Ecuadorian embassy in London for almost seven years.