Sixty MPs are calling for a significant diplomatic escalation in the case of jailed Briton Anoosheh Ashoori, who is believed to have contracted Covid-19 while serving a 10-year jail sentence in Iran. The retired engineer was detained in 2017 and convicted of spying for Israel’s intelligence agency, Mossad, following a pattern of similar sentences for dual citizens convicted on spurious charges. The MPs called on Foreign Secretary Dominic Raab to confer diplomatic protection on Mr Ashoori in the absence of a "clear strategy" for securing his release and of other Britons held in Iran. Sherry Izadi, Mr Ashoori’s wife, said: “We sincerely hope that Mr Raab will grant Anoosheh diplomatic protection, as has been done before, to demonstrate that no efforts are spared in securing his release.” Iran does not recognise the status of dual citizens and as a result refuses to allow consular officials to visit inmates such as Mr Ashoori in prison. The status of diplomatic protection would be a signal that the UK was treating the case as a formal legal dispute between Britain and Iran. The MPs’ letter said that Mr Ashoori was “more than ever” in need of official protection on a diplomatic level because of his Covid-19 symptoms and the ongoing negotiations for the release of dual citizens. He has been subjected to solitary confinement, abusive interrogations and threats to him and his family. “Diplomatic protection would not only assist the government with additional tools to urgently secure his release, but would also serve to formally recognise the grave human rights violations he has endured,” the letter said. Even if Mr Raab gives diplomatic protection it is not clear what impact it would have. Jailed charity worker Nazanin Zaghari-Ratcliffe has diplomatic protection but she is still in Iran after serving a five-year jail term before being sentenced to a further period in prison. She was fitted with an electronic tag and freed from prison in March last year owing to the pandemic and told to live with her parents in Iran. She has not been recalled to jail and the electronic tag has been removed, but she cannot leave Iran. About six British dual citizens are currently held in Iran, including two who are not publicly known owing to the wishes of their families. Mr Ashoori’s family hopes that diplomatic protection would mean all British prisoners being released at the same time if any deal was struck with Iran. Campaigners say the freedom of unfairly detained prisoners should be part of talks to revive the 2015 Iran nuclear deal in Vienna. Any deal would probably result in some sanctions lifted in return for Tehran halting its nuclear defence programme. Ms Zaghari-Ratcliffe’s husband Richard said it was unclear whether diplomatic protection had helped her but said the UK government had failed to follow it with anything credible. “It basically signals we are having a fight,” he said. “We signalled a fight but then they have done nothing. “If you are all bark and no bite you won’t be taken seriously. That is the fundamental problem for the Foreign Office. The Iranian hostage-taking industry works because they don’t fear the consequences.” He said it would require diplomatic protection to be backed up by something credible at the United Nations, legally or by imposing sanctions on key figures within the regime. Supporters of Mr Ashoori and Ms Zaghari-Ratcliffe say they are being used as pawns in a broader diplomatic battle between the UK and Iran over an unpaid £400 million ($566m) debt owed by the UK for an arms deal aborted after Iran's 1979 revolution. Decades later, the case is still working its way through the UK courts. Britain accepts it owes Iran millions of pounds after failing to deliver the armoured vehicles but says it is barred from doing so because of sanctions imposed on Iran’s defence ministry.