With three weeks remaining until a British judge decides whether to extradite him, supporters of Julian Assange say he is struggling under "atrocious" prison conditions in London.
The WikiLeaks founder is currently in the top-security Belmarsh prison, where he was moved following his arrest last year.
He is said to be in confinement following a coronavirus outbreak among other inmates. His partner Stella Morris claims conditions are dangerous.
"He's in atrocious circumstances," Morris told Sky News Australia earlier this week.
"The prison is a dangerous place, suicides and murders are commonplace, he is surrounded by very serious criminals, one in five are convicted of murder.
"And there's a COVID outbreak currently in Belmarsh prison, specifically in Julian's wing."
A judge is due to rule on January 4 on whether to extradite him to the United States.
Assange's legal battle in Britain has lasted nearly a decade since he breached bail and sought asylum at the Ecuadorian Embassy in London in 2012.
He was evicted seven years later and is now wanted on espionage charges in the US.
US prosecutors have indicted Assange on 17 espionage charges and one charge of computer misuse over WikiLeaks’ publication of secret American military documents a decade ago.
The charges carry a maximum sentence of 175 years in prison.
His supporters consider him a whistleblower who should be released, and say the conditions he would face in a US prison would breach his human rights.
Last month, Morris called on US president Donald Trump to grant Assange a full pardon before his term in the White House expires next month.
She wrote on Twitter before Thanksgiving in November: "These are Julian’s sons Max and Gabriel. They need their father. Our family needs to be whole again".
"I beg you, please bring him home for Christmas".
Euronews has asked the UK Ministry of Justice to comment on the claims of Assange's prison conditions.