The wife of a British-Iranian engineer held in prison in Tehran has said she fears he no longer stands a “hope in hell” of being released after the US strike on Iran’s top commander led the region to the brink of war.

Sherry Izadi, 56, told the Telegraph she was “terrified” that any chance of negotiation between the UK and Iran over Anoosheh Ashoori’s 10-year sentence was over.

Mrs Izadi spoke briefly to the 65-year-old retired civil engineer from Evin prison on Saturday morning: “He told me everyone there is very jittery. They are so scared of the fallout. 

“He had hoped that Iran would negotiate or relent on his release, but we feel that hope is now gone,” she said.

Mr Ashoori, who has lived on and off in the UK since he was 17, was sentenced last year after Iran found him guilty of spying for the Israeli intelligence agency, Mossad. 

Mrs Izadi said that the father-of-two was arrested by Iranian authorities in August 2017 while on a visit to see his elderly mother and that the charges against him are “preposterous.”

“I have been filled with fear since we heard the news (of Quds Force commander Qassem Soleimani's death), that there will be some act of revenge, and the prisoners will get caught in the middle.

“I don’t think Anoosheh and the Western prisoners have a hope in hell now.”

She said the Foreign Office had not been much help in her husband’s case, telling her there was little it could do as Tehran does not recognise dual nationalities.

“It all depends how British government will react to this situation now,” she said. “I’m hoping there will be a rational reaction.”

Mr Ashoori is one of as many as five people with British connections or nationality that are being held in Iran, including charity worker Nazanin Zaghari-Ratcliffe from London.

“My husband said it was funny that there were so many hostages like him in prison accused of spying, but Iran can’t have very good intelligence. He said: ‘The real spies out there passing information to the US on Soleimani’,” Mrs Izadi said.

She said her husband, who has won an award for his innovations to build earthquake-resistant homes, had been held in solitary confinement for four months.

He has since been moved to a basement ward for “security prisoners”, where 15 are kept to a room.

They are allowed to speak on the phone once a day between 11am and midday for up to 20 minutes, but Mrs Izadi worries vengeful guards might soon take away the privileges of European and American inmates.

“They call it Evin University because these cells are a full spectrum of academics - from economic experts, to lawyers, to physicists, and they have set up classes to help them cope, Anoosheh’s expertise is in aerospace engineering so he teaches that.

“He told me, ‘you either give in to the despair and wither away and die or fight them on their own terms and come out victorious’.”

As relations between Iran and the West worsened after the US withdrew from the nuclear deal with Tehran, it stepped up a campaign of sanctioned hostage-taking.

Richard Racliffe, Nazanin’s husband, accused the Islamic Republic of using its dual national prisoners as “bargaining chips”.

“For all of us who are caught between Iran and the West it will make things more difficult,” Mr Ratcliffe said on Friday, speaking after the US raid. “How we get out of the situation, goodness knows at this point.”

Mrs Zaghari-Ratcliffe, 40, has gone on a hunger strike, alongside British-Australian academic Kylie Moore-Gilbert, in protest at losing appeals to overturn their espionage convictions.

Iran called the US strike on Soleimani’s convoy an act of ”'international terrorism” and the country's supreme leader Ayatollah Ali Khamenei vowed that 'harsh revenge is waiting for the criminals' who killed Soleimani.

Experts have warned of retaliations from Iran following the strike.

Alistair Burt, former Middle East minister, said the situation is “extremely serious” and could cause “a huge potential escalation of the conflict, of which the consequences are unknown.”