A British-Iranian labour rights campaigner has been held in solitary confinement in Iran's Evin jail for five months after authorities secretly monitored political meetings of activists in a Tehran coffee shop, a friend told <em>The National</em>. Mehran Raoof was rounded up on October 16 with a group of other labour activists. His only contact with the outside world since then was a short telephone call with a distant relative in Iran. Previous cases suggest he was tortured and forced to confess before a sham trial, rights campaigners said. Friends believe Mr Raoof, 64, was caught after the gathering of more than a dozen labour activists in Tehran was secretly recorded and those involved tracked by security agents. "The arrests were in October but before that for three months they used to go to a place like a coffee shop to talk about workers' problems in Iran," said Satar Rahmani, a UK-based colleague. "They talked about politics, but someone was spying on them without them knowing." Some of Mr Raoof's colleagues who have since been released said their interrogators were able to recite their exact conversations and give precise details of their movements over weeks. “One of them said: 'They knew everything. Every place I went, everything I said. The prison officers said: 'You can’t lie to us – we know everything’,” said Mr Rahmani, who has been in contact with the activists. Mr Raoof was arrested at his flat in Tehran and officials seized his computer and phone during the co-ordinated crackdown against labour rights activists. One of those held in the sweep, Arash Johari, was sentenced to 16 years in prison on spurious national security charges, raising fears of harsh sentences for others. Mr Raoof potentially represents added value for the regime because his detention follows the pattern of arrests of dual citizens for use as bargaining chips with other countries as Iran pursues its foreign policy goals. He is one of a number of Britons detained or refused permission to leave Iran that includes Nazanin Zaghari-Ratcliffe, 42. Ms Zaghari-Ratcliffe is expected to learn her fate this week after a second trial, despite having served a five-year term on what the UK government considers trumped-up security charges. Mr Raoof, who was born and raised in Iran, studied mechanical engineering in Huddersfield, West Yorkshire, before the 1979 revolution. He later lived in Islington, London, and was active in politics and workers’ rights in the UK and Iran, said Mr Rahmani, who has known Mr Raoof since the 1980s. He now spends most of his time in Tehran where he worked as an English teacher and translator. Mr Raoof's current circumstances are unknown, and he was not able to give details of his detention when the distant relative called the prison. “He couldn’t say anything other than I’m OK,” Mr Rahmani said. His friends and family in France and the US have heard nothing for more than three months. Mr Raoof is being held in the Islamic Revolutionary Guard Corps-controlled section 2A of Evin prison, where inmates are taken from their cells only for interrogation. Prisoners in solitary confinement are often held without access to light and fresh air, in filthy, insect-infested cells. They usually sleep on the floor with a single blanket and receive poor-quality rations. The case was taken up by Amnesty International, which called on the Iranian authorities to "immediately end his prolonged solitary confinement and protect him from further torture and other ill-treatment". Iran does not recognise dual-national citizens and consular officials of overseas governments have been denied visiting rights. Mr Raoof's family has not made a direct request to the UK goverment to intervene in the case. The British foreign ministry said: “We continue to raise the issue of British dual national detentions with the Iranian authorities”. Mr Raoof was arrested on the same night as Nahid Taghavi, 66, a German-Iranian citizen, who was also held for months in an area of the Tehran jail controlled by the IRGC. Her family said she was released into the mainstream women’s wing for the first time on Tuesday after 151 days in the IRGC section of the prison. It is not known if Ms Taghavi, a campaigner for women’s rights, was at the cafe meetings. "This is a first victory but the campaign for her unconditional and immediate release has to be continued," said Mariam Claren, Ms Taghavi's daughter. “For today, I am happy that my mother is not isolated any more and has the opportunity to talk with all the strong and brave women who are behind bars with her. We should all continue campaigning to free them all.”