The British-Iranian national being held in Iran, Nazanin Zaghari-Ratcliffe, has had her British passport returned, her MP in the UK Tulip Siddiq has said.
Ms Siddiq says she understands there is a British negotiating team in Tehran where she is being detained.
The MP for Hampstead and Kilburn tweeted: “I am very pleased to say that Nazanin Zaghari-Ratcliffe has been given her British passport back.
“She is still at her family home in Tehran. I also understand that there is a British negotiating team in Tehran right now.
“I will keep posting updates as I get them.”
A British-Iranian dual national, Mrs Zaghari-Ratcliffe has been in custody in Iran since 2016 after being accused of being a spy.
She was taking her daughter to visit family when she was arrested at Tehran Airport and sentenced to five years in jail, spending four in Evin Prison and one under house arrest.
She was later sentenced to a further one year plus a one-year travel ban, prompting fears she would be sent back to prison.
According to her family, she was told by local authorities that she was being detained because of the UK’s failure to pay an outstanding £400m debt to Iran.
In December, Foreign Secretary Liz Truss said the £400 million that Britain owes Iran is a “legitimate debt” that the government wants to pay.
Mrs Zaghari-Ratcliffe’s husband Richard Ratcliffe has been outspoken in calling for her release, including camping outside the Foreign Office in London on a three-week hunger strike in November 2021.
Sacha Deshmukh, Amnesty International UK’s chief executive, warned that the latest reports should be treated with caution as there had been “false dawn after false dawn” in the long-running process.
He said: “We sincerely hope these reports are correct.
“The detainees and their families have been suffering for years, and a resolution can’t come quickly enough.”