Pamela Anderson has described Julian Assange as “the world’s most innocent man” and said a fight was on to “save his life”, after the actor and model visited the WikiLeaks founder at Belmarsh prison.

She was accompanied by the website’s editor-in-chief, Kristinn Hrafnsson, for what WikiLeaks described as Assange’s first social visit since he was arrested by police after Ecuador revoked the political asylum granted to him at the country’s London embassy.

A struggle over a US request for Assange’s extradition is under way after he was jailed for just under a year for breaching bail conditions to avoid being extradited to Sweden. Assange took refuge in the Ecuadorian embassy in 2012 to avoid extradition over sexual assault allegations, which he denies.

Q&A Why was Julian Assange in the Ecuadorian embassy? Show Hide An arrest warrant for Assange was issued in August 2010 for two separate sexual assault allegations in Sweden. Police questioned him in Stockholm, where he denied the allegations. After returning to the UK, he feared that if he were extradited to Sweden he might be extradited on to the US, where he could face charges over WikiLeaks’ publication of secret US government files. In December 2010 he appeared at an extradition hearing in the UK, where he was granted bail. Following a legal battle, the courts ruled Assange should be extradited to Sweden. The WikiLeaks founder entered the Ecuadorian embassy in August 2012. He was granted political asylum, and remained there until his arrest. In May 2017, Swedish authorities dropped their investigations. However, the British police warrant for his arrest for skipping bail still remained. Lawyers for Assange failed in January 2018 to have the warrant torn up, arguing it had “lost its purpose and its function”. Scotland Yard has confirmed that Assange was arrested on behalf of the US after receiving a request for his extradition and the US has charged Assange with 'a federal charge of conspiracy to commit computer intrusion for agreeing to break a password to a classified U.S. government computer.' Jamie Grierson, Home affairs correspondent

“He does not deserve to be in a supermax prison. He has never committed a violent act. He is an innocent person,” Anderson said outside the prison in south-east London, which is a maximum-security jail but holds a range of prisoners.

Anderson said he was “really cut off from everybody” and had not been able to access the internet, use a library or speak to his children.

“He is a good man, he is an incredible person. I love him, I can’t imagine what he has been going through,” said Anderson, who was wearing what appeared to be a cape covered with text that made references to prison, tyranny and Oliver Cromwell.

She tweeted a link to a Wikipedia page for John Lilburne, an English Leveller who was a friend of Cromwell but whose opposition to the policies of his regime led to his trial for sedition in 1649. She also tweeted a photograph of a handwritten letter that appeared to have been signed by her and another celebrity supporter of Assange, the fashion designer Vivienne Westwood.

“We need to save his life. That is how serious it is,” Anderson said.

Hrafnsson, who last week criticised “austerity and cutbacks” in the prison system and said Assange usually spends 23 hours a day in his cell, added: “He has lost weight but his spirit is strong and that is the most important thing.”

During a court appearance last Thursday, Assange declined a chance to consent to his extradition to the US in a hearing at Westminster magistrates court, where lawyers for Washington began pressing the case to take him across the Atlantic. Ben Brandon, the counsel for the US government, said the charges related to one of the largest compromises of information in US history.

Swedish prosecutors have said they are considering reopening the investigation into rape and sexual assault allegations against Assange.