Lawyers for a British-Iranian man serving a 10-year sentence in Tehran's notorious Evin prison say there is an "imminent threat" to his life after a cellmate exhibited symptoms of Covid-19.
The legal team for Anoosheh Ashoori, 66, said a 74-year-old man imprisoned with him had "very high temperature and excruciating body aches" and urged the British government to take immediate steps to secure their client's release on furlough.
Mr Ashoori, a retired engineer, was detained in August 2017 while visiting his mother and accused of passing intelligence to Israel. He has described the prison as a "hellhole" and voiced concerns about the unhygienic conditions.
Iran has a history of convicting dual nationals on espionage-related charges and using them as bargaining chips.
Mr Ashoori's legal team said he had been "arbitrarily detained for over three years and subjected to gross violations to his fundamental fair trial and due process rights, as well as his right against torture".
"The conditions of his detention have breached international minimum standards for the treatment of prisoners, and reports of the virus within proximity of Mr Ashoori now risks violating his right to health and life if immediate steps are not taken," they said.
While the release of Mr Ashoori and return to his family in the UK remains the ultimate priority, his legal team said his furlough or supervised release from Evin prison "must be urgently secured as a safeguard to his health and well-being while further steps for his release are taken".
The UK's Foreign, Commonwealth and Development Office have been approached for comment.