Two dual UK-Iranian nationals have been released from custody, the authorities in Tehran said on Wednesday, ending a lengthy ordeal after years of diplomatic wrangling between the two countries over a cancelled defence deal.

Iranian state broadcaster IRIB said Nazanin Zaghari-Ratcliffe had been "handed over" to the UK authorities, while the judiciary also confirmed the release of Anoosheh Ashoori.

The pair's release came after UK Foreign Secretary Liz Truss indicated that London and Tehran had resolved a ?400-million ($520-million, 475-million-euro) debt dating back to the time of the Shah of Iran.

The families of both Zaghari-Ratcliffe and Ashoori believe they were being held as political prisoners until the issue was settled.

Truss told BBC radio on Wednesday she had made it "a priority to ensure that we are paying back the debt that we legitimately owe the Iranian authorities".

The UK has consciously avoided saying the detention of the pair, and others held in Iran, was linked to the debt, related to an order of tanks that was cancelled after the 1979 Islamic revolution.

Truss said the issues were separate and blamed sanctions on Iran for delaying the repayment.

UK-Iranian dual national Nazanin Zaghari-Ratcliffe has been held since 2016 but has now been handed over to the UK authorities, Iranian state TV said
UK-Iranian dual national Nazanin Zaghari-Ratcliffe has been held since 2016 but has now been handed over to the UK authorities, Iranian state TV said Free Nazanin campaign via AFP

There was no immediate official confirmation in London of the pair's release. Deputy Prime Minister Dominic Raab said only that reports they were coming home "feels like positive signs".

And he dismissed suggestions from the main opposition Labour party that Prime Minister Boris Johnson had worsened the situation by making comments about the reasons for Zaghari-Ratcliffe's detention when he was foreign secretary.

He told Labour deputy leader Angela Rayner: "She shouldn't give succour to the despotic regime that detained our nationals in Iran or around the world by suggesting it is anyone else's responsibility other than theirs."

Zaghari-Ratcliffe, a project manager for the Thomson Reuters Foundation, the philanthropic arm of the news and data agency, was arrested in Tehran on a visit to family in 2016.

The mother-of-one, from north London, was sentenced to five years in prison for plotting to overthrow the government.

Last year she was given a further 12-month jail term for taking part in a rally outside the Iranian embassy in London in 2009.

Another dual national, Anoosheh Ashoori, has been held in Iran since 2017
Another dual national, Anoosheh Ashoori, has been held in Iran since 2017 AFP / DANIEL LEAL-OLIVAS

Ashoori, a retired engineer from southeast London, was arrested in 2017 and jailed for 10 years on charges of spying for Israel.

Both have strenuously denied the charges, while Ashoori in January began a hunger strike at Tehran's Evin prison.

Hopes were raised about Zaghari-Ratcliffe's release after she had her British passport returned to her on Tuesday while a UK negotiating team was in Iran.

On Wednesday, her local MP Tulip Siddiq said Zaghari-Ratcliffe was "at the airport in Tehran and on her way home". She also praised Truss for her efforts.

Sacha Deshmukh, Amnesty International UK's chief executive, welcomed the "fantastic news" of the release, saying both were "jailed on trumped-up national security charges".

"The government needs to follow up on Nazanin and Anoosheh's release by immediately renewing its calls for the release of the UK nationals Mehran Raoof and Morad Tahbaz, both of whom are still going through an ordeal all too similar to Nazanin and Anoosheh's," he added.

Raoof, a labour rights activist, was detained in October 2020 and was being held in solitary confinement, according to Amnesty.

Tahbaz, an Iranian-American who also holds British nationality, was arrested alongside other environmentalists in January 2018 and sentenced to 10 years in jail for "conspiring with America".

Dual nationals from Austria, Canada, France, Germany, Sweden and the United States have also been arrested in similar circumstances.

Richard Ratcliffe staged a hunger strike outside the foreign ministry in London last October after his wife lost her latest appeal, and as government ministers held talks with Iranian counterparts.

She was freed from prison with an electronic tag in March 2020 because of the coronavirus pandemic but had been held in Iran under a form of house arrest ever since.

Ashoori went on hunger strike having failed to see "any progress" in British efforts to bring about his release and "no sign the welfare of hostages held by Iran is a priority of the US, European and UK governments", his daughter Elika Ashoori said.

Campaigners and families of those held have said that the issue of detainees is being forgotten by the West as powers seek to negotiate a revival of the 2015 deal on the Iranian nuclear programme in Vienna.