Hopes that Nazanin Zaghari-Ratcliffe could be released as part of a prisoner swap appear to have been dashed after Iran backed away from reports of a possible deal.

Iranian foreign minister Javad Zarif had appeared to suggest the British-Iranian mother, who was jailed in 2016 after being convicted of spying, which she denies, could be freed in exchange for an Iranian woman held in Australia on a US extradition request.

But in a later interview he said Mrs Zaghari-Ratcliffe was a “separate case” from those prisoners held at the behest of the Americans.

“The offer that I made was people who have been in prison either in the United States or elsewhere in the world on American request. But the Iranian-British woman is a separate case,” he told Reuters.

Downing Street confirmed that the government had not received any approach from Tehran about a possible prisoner exchange.

UK foreign secretary Jeremy Hunt said it was “unfortunate” that the Iranian foreign minister appeared to have “somewhat retracted” his offer.

Nazanin Zaghari-Ratcliffe – in pictures Show all 20 1 /20 Nazanin Zaghari-Ratcliffe – in pictures Nazanin Zaghari-Ratcliffe – in pictures 2018 Nazanin Zaghari-Ratcliffe hugs her daughter Gabriella, in Iran after she was allowed to leave the Iranian prison, she is being held in, for three days. Zaghari-Ratcliffe was arrested during a holiday with her toddler daughter in April 2016. Iranian authorities accuse her of plotting against the government. Her family denies this, saying says she was in Iran to visit family. Free Nazanin Campaign/AP Nazanin Zaghari-Ratcliffe – in pictures Nazanin Zaghari-Ratcliffe with her husband Richard Ratcliffe and their daughter Gabriella. Nazanin is serving a five-year prison sentence for allegedly plotting to overthrow Iran's government. PA Nazanin Zaghari-Ratcliffe – in pictures June 2016 Richard Ratcliffe's daughter Gabriella had her British passport confiscated and was stranded in Iran with her grandparents after her mother Nazanin was jailed. He left left a giant birthday card on the doorstep of the Iranian embassy in central London to mark her second birthday in June 2016. PA Nazanin Zaghari-Ratcliffe – in pictures Nazanin has spent some of her prison sentence in solitary confinement. PA Nazanin Zaghari-Ratcliffe – in pictures Nazanin Zaghari-Ratcliffe with her husband Richard and daughter Gabriella. Family Handout Nazanin Zaghari-Ratcliffe – in pictures July 2016 Richard Ratcliffe delivering a letter of petition with his mother Barbara Ratcliffe and MP Tulip Siddiq, to 10, Downing Street on the 100th day of her detention, on July 12, 2016. Getty Nazanin Zaghari-Ratcliffe – in pictures Supporters of Nazanin Zaghari-Ratcliffe held a vigil outside the Foreign and Commonwealth Office to mark her 707 days in captivity. Getty Nazanin Zaghari-Ratcliffe – in pictures January 2017 Richard Ratcliffe holds a '#Free Nazanin' sign and candle during a vigil for for wife on January 16, 2017. The vigil, being held outside the Iranian Embassy in London marks one year since the Washington Post journalist Jason Rezaian and other US-Iranian dual-nationals were released from prison in Iran. Getty Nazanin Zaghari-Ratcliffe – in pictures Nazanin with her daughter Gabriella before they were detained by Iranian authorities. Change.org Nazanin Zaghari-Ratcliffe – in pictures September 2017 Gabriella, who is three-years-old in this picture, has now spent two years away from her mother. Richard Ratcliffe Nazanin Zaghari-Ratcliffe – in pictures November 2017 Foreign Secretary Boris Johnson meets with Richard Ratcliffe over Nazanin's case. They meet just days after Johnson told a parliamentary committee that she was in Iran "training journalists". WPA Pool/Getty Nazanin Zaghari-Ratcliffe – in pictures November 2017 Actor Emma Thompson braved pneumonia to support Richard Ratcliffe in leading demonstrators before a march in support of Nazanin in November. Reuters Nazanin Zaghari-Ratcliffe – in pictures November 2017 Richard Ratcliffe after the march said: 'It is profoundly moving to see so many people here.' REUTERS Nazanin Zaghari-Ratcliffe – in pictures November 2017 A picture of Nazanin Zaghari-Ratcliffe shown on Iranian state TV as part of a report that made fresh allegations against her. They said she had been recruiting for banned broadcast services, as well as 'opposition cyber teams'. Nazanin Zaghari-Ratcliffe – in pictures December 2017 Iranian president Hassan Rouhani greets British Foreign Secretary Boris Johnson at the presidential office in Tehran, Iran. Johnson visited Tehran to discuss the fate of detained Nazanin Zaghari-Ratcliffe. EPA Nazanin Zaghari-Ratcliffe – in pictures Nazanin Zaghari-Ratcliffe with her daughter Gabriella. PA Nazanin Zaghari-Ratcliffe – in pictures December 2017 Photos of Richard Ratcliffe and his wife Nazanin Zaghari-Ratcliffe on display at their home in north London. Mr Ratcliffe said he believed there was "still a chance" she may be released from an Iranian prison in time for a dream Christmas together. Unfortunately that didn't happen. PA Nazanin Zaghari-Ratcliffe – in pictures February 2018 Richard Ratcliffe delivers a petition and a letter addressed to the Iranian Deputy Foreign Minister Abbas Araghchi to demand her release, at the Iranian Embassy in London on February 21, 2018. He also left support letters for his spouse in the country's embassy, amid a visit by a deputy foreign minister. AFP/Getty Nazanin Zaghari-Ratcliffe – in pictures August 2018 Foreign Secretary, Jeremy Hunt meeting Richard Ratcliffe. Hunt has pledged to do everything possible to secure the release of a charity worker jailed in Iran Jeremy Hunt/PA Nazanin Zaghari-Ratcliffe – in pictures August 2018 Nazanin Zaghari-Ratcliffe hugs her daughter Gabriella, in Iran after she was allowed to leave the Iranian prison, she is being held in, for three days. Zaghari-Ratcliffe was arrested during a holiday with her toddler daughter in April 2016. Iranian authorities accuse her of plotting against the government. Her family denies this, saying says she was in Iran to visit family. PA

“Nazanin Zaghari-Ratcliffe is innocent,” he added. “What is unacceptable about what Iran is doing is the fact that they are putting innocent people in prison and using it in leverage.

“The thing that we mustn’t forget in the Nazanin case is that there are other Brits or dual nationals in exactly the same situation as Nazanin, whose families have chosen not to go public with their names.”

Mr Hunt praised Nazanin’s husband Richard Ratcliffe for his courage in making sure “the whole world knows about this Iranian practice.”

He added: “It’s not just the Brits – it happens to dual nationals from many western states. I hope that the outcome of this will not just be freedom for Nazanin but actually the ending of this practice by Iran, which is absolutely vile.”

Ms Zaghari-Ratcliffe was arrested at Tehran’s Imam Khomeini airport on 3 April 2016, when trying to return to London after a holiday with her then 21-month-old daughter, Gabriella.

She was later held in solitary confinement for eight months, before being handed a five-year jail sentence on espionage charges, which she denies.

Mr Zarif had previously appeared to link the case of Mrs Zaghari-Ratcliffe with that of the woman held in Australia.

“I feel sorry for them and I have done my best to help, but nobody talks about this lady in Australia who gave birth to a child in prison whose child is growing up outside prison with mother in prison,” he said.

“So, what can I do as a foreign minister? And I put this offer on the table publicly now. Exchange them.”

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Theresa May’s official spokesman said it was his understanding that the Iranian foreign minister had clarified his initial comments.

“The treatment of all British-Iranians detained in Iran, including Nazanin Zaghari-Ratcliffe, is a priority for the government,” the spokesman added.