A British-Iranian labour activist arrested in Iran faces a minimum 10-year jail term after being accused of being the leader of a communist cell, his supporters have learned. Mehran Raoof, 64, has been held in solitary confinement at Tehran’s Evin jail since he was detained in October last year, along with other labour and human rights activists who gathered in a Tehran café. He has only been seen once by his lawyer at a hearing last month when he was accused of unspecified security offences, but a 200-page file seen by his legal team now accuses him of being the leader of a banned communist group. His laptop was seized when officials arrested him at his Tehran flat and its contents are being used to build the case against him. Iranian communists opposed the rule of the Shah before the 1979 revolution but the clerical regime banned the party and turned on its leaders in the early 1980s. Hundreds of left-wing prisoners were among those killed in the 1988 prison massacres that targeted opponents of the regime. Mr Raoof, who has campaigned on behalf of Tehran transport workers, is due back in court next month. He went on hunger strike to protest against his detention. During his appearance before a judge last month, he told his lawyer he needed funds to supplement his meagre supplies in Evin. His supporters are urging the UK government to demand an independent medical examination because of fears over his deteriorating health. Mr Raoof's lawyer is expected to appeal to the prison authorities this week to return him to the mainstream prison population before the second stage of his trial. “We have heard from friends that he has lost a lot of weight and does not look very healthy,” said Satar Rahmani, a UK-based supporter. “But we don’t know what problems he has because he is unable to talk to us.” At least 15 dual nationals are believed to be held by the Iranian regime, according to the US-based Center for Human Rights in Iran. Their arrests generally follow a pattern of prolonged solitary confinement and interrogations, denial of consular visits, secretive trials and long sentences for national security offences. The detentions are often used as bargaining chips to secure Iran’s broader diplomatic goals.