Charity worker Nazanin Zaghari-Ratcliffe is “overwhelmed” and “very happy” after being temporarily released from prison in Iran for three days, her husband has said.

The British-Iranian mother has been reunited with four-year-old daughter Gabriella and other family members after spending 873 days in jail.

She was sentenced to five years in jail after being accused of spying by Tehran’s Islamist regime.

Mrs Zaghari-Ratcliffe, from Hampstead, north London, has consistently denied all allegations, insisting she was on holiday to introduce her daughter to family.

Nazanin Zaghari-Ratcliffe detainedNazanin Zaghari-Ratcliffe with daughter Gabriella, after her temporary release (Handout/PA)

The 39-year-old was released from Evin prison in Tehran on Thursday morning and is now with family in Damavand, just outside the capital, until Sunday, according to the Free Nazanin campaign.

Husband Richard Ratcliffe welcomed the “good step”, saying: “Despite the build-up, today was a genuine surprise after all the disappointments.

“We have been burned by hope before, so it had been easier to presume disappointment would come again.

“But it didn’t – she is outside those prison walls. And we are all so pleased.”

Mrs Zaghari-Ratcliffe said: “I was so emotional to see my grandmother today. I cried so much. I felt so overwhelmed. My dad’s home is not my home – but it is so much better than prison.

“People in the ward were so excited – they sang songs and danced. I baked for them in celebration. It felt like this really could be the beginning of the end.”

Her lawyer will apply to extend the furlough and several of her cellmates remain out of prison more than a month after being granted the same three-day period initially.

Speaking ahead of a UN briefing, Foreign Secretary Jeremy Hunt said: “It is extremely positive and we want to thank the Iranian authorities for what they’re doing, whilst not forgetting that she should not be imprisoned in the first place.

“Nazanin is innocent. She has a four-year-old daughter, Gabriella. She has a devoted husband. She has friends in both Iran and the UK and frankly every day that she is in prison is a reminder to the whole world of a gross injustice.

“So we call on the Iranian authorities to capitalise on the goodwill from today’s announcement by going the whole way and releasing Nazanin and allowing her to go back to her family and come back to the UK, which is where her home is, and end this totally appalling injustice.”

Mr Hunt also said his predecessor Boris Johnson made “enormous efforts” to try to free her.

Describing the family reunion, Mr Ratcliffe said his wife was “overwhelmed”.

He said: “She (Nazanin) was very happy on the phone, though confessed to having cried lots, particularly when seeing her grandmother, and to being still overwhelmed.”

Mr Ratcliffe also thanked Mr Hunt for “all his recent efforts and considerations”.

Former foreign secretary Mr Johnson last year apologised for the “distress” and “suffering” he caused by suggesting Mrs Zaghari-Ratcliffe was training journalists in Iran, which exposed her to the threat of her five-year jail sentence being doubled.

Mrs Zaghari-Ratcliffe, who works for the Thomson Reuters Foundation, is facing a further hearing over an unspecified security charge which her family believes will include an accusation of spreading propaganda against the Iranian regime.

The mother-of-one has been used as a political pawn, according to Nobel Laureate and Iranian human rights lawyer Shirin Ebadi.

She said in June: “Yes, Nazanin Zaghari-Ratcliffe is being used as a political pawn but it is not just her.

“There are currently over 30 dual nationals that are being held in Iran, so pressure must be put on the Iranian government in that regard.”

On Tuesday, Mr Hunt said he was considering whether to grant diplomatic protection as a means of freeing her.

He told BBC Radio 4’s Today programme that he had been going over the case in an “enormous amount of detail” and was considering a request by her husband to grant her diplomatic protection.

Mr Hunt said he had not “come to a final decision” on the issue and said there were “pros and cons”.