Nazanin Zaghari-Ratcliffe has left Iran after six years of detention, a source close to the family has said.
It comes a day after it was announced the British-Iranian mother had been handed back her British passport, creating new home that she finally be reunited with her family.
Ms Zaghari-Ratcliffe was released with another detained Briton, Anoosheh Ashouri, who is also due to come back to the UK today according to their lawyer.
Their release comes nearly six years after Ms Zaghari-Ratcliffe was first detained in the country, and five years since Mr Ashouri’s arrest.
Her MP, Tulip Siddiq, said the mother-of-one had arrived at the airport in the Iranian capital Tehran and was “on her way home”.
However the UK Government has yet to officially confirm the departure, as the situation continues to develop.
Ministers had previously said a British team was in Tehran working to secure her release. Boris Johnson said on Tuesday that those negotiations were going “right up to the wire”.
Richard Ratcliffe’s sister has said it felt like they were on the “home run” following the news that she had been had been taken to the airport.
Rebecca Ratcliffe told the BBC: “It is quite emotional day today. It feels like we are on the home run now but until she leaves that airport we can’t quite believe it.
“We found out about an hour ago that Nazanin had been picked up and taken to the airport with her parents. She is still actually under Iranian control in the airport.
“She is still not free but it definitely feels she is about to be.”
Ms Zaghari-Ratcliffe spent five years in jail in Iran after being taken into custody at Tehran airport while visiting family in April 2016.
The aid worker was later convicted of plotting to overthrow Iran’s government - a charge vehemently denied by both Ms Zaghari-Ratcliffe and rights groups.
She had been held under house arrest and unable to leave Iran since her release from prison. Last spring, she was sentenced to another year in jail on charges of propaganda against Iran’s ruling system - which she denies - that had not yet started.
The detention of the project manager for the Thomson Reuters Foundation, the charitable arm of the Reuters news agency, sparked a tireless campaign for her release.
Towards the end of last year, her husband spent 21 days on hunger strike outside Downing Street.
Tulip Siddiq told Sky News on Wednesday: “I’ve spoken to Richard Ratcliffe who said that Nazanin is now at the airport in Tehran, but made the point that she is very much still under the authority of the Iranian Revolutionary Guard, and that there has been no information about a deal.
“However, Richard is taking heart from the fact that his wife is at the airport in Iran, she does have her British passport back.”
Ms Siddiq added: “The way he described it to me is that he feels that they can smell freedom, they just haven’t grasped it yet. As you can imagine, Richard is very emotional, patiently waiting as he has been for six years, but doesn’t have confirmation that his wife is on the flight yet.”
Sadiq Khan, the mayor of London, said he was “delighted” at the news Ms Zaghari-Ratcliffe was “on her way home to be reunited with her family”.
“Nazanin and her loved ones have shown great courage, strength and steadfastness through this unimaginably difficult time. London looks forward to welcoming her home,” he tweeted.
Her release comes alongside Mr Ashouri, a retired civil engineer who was sentenced to 10 years in jail on spying allegations in 2019, which he denies.
Earlier this year, his daughter said the British-Iranian, who is in his late 60s, had gone on hunger strike.
The release of the detainees came as Tehran and London pressed on with talks about a long-standing £400m debt.
Liz Truss, the British foreign secretary, said on Tuesday it was also a “priority to pay the debt that we owe to Iran”, which relates to a cancelled order for 1,500 Chieftain tanks from the 1970s.
Both the UK and Iran’s government have insisted there was no connection between the debt and Ms Zaghari-Ratcliffe’s case.
