Boris Johnson has been accused of a “dismal failure” in his diplomatic efforts after Iran sentenced Nazanin Zaghari-Ratcliffe to a further year in jail on top of the five-year sentence she has already served. Labour’s Tulip Siddiq, the British-Iranian dual national’s MP, questioned the effort the prime minister had put into releasing Zaghari-Ratcliffe, telling the Commons: “From where I’m standing, I’ve seen no evidence on the part of the prime minister so far. “At the heart of this tragic case is the prime minister’s dismal failure to release my constituent and to stand up for her, and his devastating blunder in 2017 when he was foreign secretary – when he exposed his complete ignorance of this tragic case and put more harm in Nazanin’s way. “The prime minister did not even arrange for UK officials to attend Nazanin’s recent court hearing, which might have ensured she got a free and fair trial. He still hasn’t got his government to pay the £400m debt that we as a country owe Iran.” It is one of the most unbridled attacks on the Foreign Office’s handling of the case by the MP, who is deeply frustrated at the government’s inability over five years to have any impact on the Iranian revolutionary courts. Siddiq said there was a link between the extra sentence and the delay of a court hearing into the £400m debt owed by the British government, arising from the cancellation of arms contract to Iran dating back to 1979. “At the moment we can’t negotiate with them properly because they don’t trust us and we haven’t paid the money,” she said. Richard Ratcliffe, Zaghari-Ratcliffe’s husband, fears her fate has now become more intertwined with talks in Vienna over the future of the Iran nuclear deal, and the lifting of US sanctions. He said his wife was very angry at the unfairness of a second sentence. He said she wanted to speak to the foreign secretary, Dominic Raab, to ask why his assurances that progress was being made “had not worked out. It needs much more than sympathy to get her home.” Ratcliffe said their daughter Gabriella had probably picked up at the school gates that something was going on with her mother, but Nazanin did not want to tell the six-year-old exactly what happened since as yet she is still staying at her parent’s home and not ordered back to prison. Richard said he would not hide it from her. He pointed out that if his wife is not allowed to return until 2023, as the new sentences suggest, she will not have seen him for seven years and their daughter for three and a half years. He told the BBC: “That is a very long time to be wrapped up in someone’s else’s fight. There is something very hard for her to be powerless in someone else’s battles. There is a legacy of other people’s lives being taken apart due to this.” The government needed to examine the consequences for other people of the choices it makes, he said, including the £400m debt the UK owes Iran over the non-delivery of tanks. “The debt and all the hostages are all wrapped up in a big grand push to solve things,” he said. “The risk we then get embroiled in lots of complex disputes that could take a very long time to solve.” Raab, speaking at a Lords select committee on Tuesday, said: “There is clearly scope for a deal to be done in which Iran returns to full compliance with the JCPoA [the 2015 nuclear deal] and address wider issues of concern in the region.” He added that there was “a chance, an opportunity, before the Iranian presidential elections in June and we will know by then if we have been successful”. Raab said “there were two paths for Tehran, one of which is to go further and further into economic and political isolation, and there is a better route for the Iranian people”. He said the balance of power between the different factions in Iran could not be judged one day to the next. “You see a constant tension and you have to take a step back, and take a bigger picture view of it.” The crisis came as Iran remained convulsed by the leak of an audio tape in which the foreign minister, Javad Zarif, was heard accusing the Islamic Revolutionary Guards Corps of dominating foreign policy. The leak, extracted from a seven-hour interview, has led to hardliners claiming Zarif, in discussing the interplay between diplomacy and the battlefield, had insulted the assassinated former Islamic revolutionary Guards Corps leader Qassem Suleimani. A furious Iranian foreign ministry said the tape had been stolen and its broadcast was part of a conspiracy against “the government, the system, internal cohesion, our efficient institutions in the fields, as well as a conspiracy against our national interests”. Some see the leak as part of an effort to destabilise the talks in Vienna and weaken the foreign ministry negotiators.