A judge has ruled WikiLeaks founder Julian Assange should not be extradited to the United States because of his mental health.

Judge Vanessa Baraitser said there was a “real risk” Assange, 49, would be locked up at the Administrative Maximum Facility (ADX) in Florence, Colorado – home to terrorist Abu Hamza – if convicted.

There are currently nine inmates subject to special administrative measures (Sams) for espionage inside the prison.

If made subject to the full restrictions, Assange would be kept in conditions of “significant isolation” and “contact with his family will be curtailed,” the judge said.

“Time out of his cell will be spent exercising in a small room or cage alone.”

The judge found Assange suffers from a recurrent depressive disorder and accepted the evidence of Dr Quinton Deeley, a consultant neuropsychiatrist, that he suffers from high-functioning Autistic Spectrum Disorder (ASD) and Asperger’s.

“Notwithstanding the strong and constant support he received from his family and friends Mr Assange has remained either severely or moderately clinically depressed throughout his detention at HMP Belmarsh,” she said.

At an evidential hearing in the autumn, psychiatrist Professor Michael Kopelman said Assange was at a “high risk” of taking his own life, having made preparations including confessing to a Catholic priest.

Prof Kopelman told the Old Bailey he visited Assange some 20 times in Belmarsh, where he is still being held on remand ahead of a bail hearing on Wednesday.

The emeritus professor of neuropsychiatry at King’s College London, said Assange has suffered from auditory hallucinations and the court heard he has frequently called the Samaritans from prison.

He said the combination of Assange’s depression and ASD has caused an “almost obsessional rumination” on the topic of suicide.

“He’s made various plans and undergone various preparations, such as confessed to the Catholic priest, who granted him absolution, began to draft farewell letters to family members and close friends, he’s drawn up a will. Various preparations are in place,” he said.

The court heard Assange was put in solitary confinement after prison guards found a razor blade in a pile of underpants in his cell, while two cords were confiscated in another incident.

Prof Kopelman told the court Assange has a genetic predisposition to depression and has suffered a number of episodes, including whilst in the Ecuadorian embassy in London, where he stayed for almost seven years.

Judge Baraitser said on Monday: “I’m satisfied that Mr Assange has the intellect and determination to circumvent suicide prevention measures.”

She added: “Faced with the conditions of near total isolation without the protective factors which limited his risk at HMP Belmarsh, I am satisfied the procedures described by the US will not prevent Mr Assange from finding a way to commit suicide and for this reason I have decided extradition would be oppressive by reason of mental health and I order his discharge.”