A British Council employee, jailed for 10 years for spying in Tehran, is a “hostage” being used by Iran’s regime to put pressure on the UK, her fiance said. Iranian Aras Amiri, detained in March on a trip to visit her “critically ill” elderly grandmother, had an appeal against her sentence rejected this week. She is being held in the notorious Evin Prison in Tehran where British-Iranian charity worker Nazanin Zaghari-Ratcliffe worker is also imprisoned. "She was led into a series of interrogations, imprisoned, solitary confinement and then a period of interrogations over two months," Ms Amiri's fiancé James Tyson told the BBC<em>.</em> He said he believes the case is “actually a problem between the UK and Iran.” Relations between Tehran and London have been increasingly strained in recent months with Iran detaining the British-flagged oil tanker <em>Stena Impero</em> in the Arabian Gulf in July. This came in response to the seizure of an Iranian vessel off Gibraltar by UK forces, which was head to Syria in violation of European Union sanctions. It has since been released. "It's one of those cases where you know that what's happening is being done for public effect," Mr Tyson said. Ms Amiri was arrested because of her work for the British Council, where she has worked for five years, he added. Previously, she had typically visited Iran once or twice a year “without any problem whatsoever,” he said. "As much as one can try to work within the official channels, one knows that actually we're dealing with a situation about the impression that Iran wants to make to the UK, the pressure they want to put on the UK,” he said. "And using Aras in this way as a bargaining chip or hostage of some kind to try get what they want, some advantage in their relationships with the UK." Mr Tyson said the British government “at some” level had to be responsible for her fate because of who she worked for. She reportedly only found out her sentence from a TV report.