"So we call on the Iranian authorities to capitalize on the goodwill from today's announcement by going the whole way and releasing Nazanin and allowing her to go back to her family".
British-Iranian charity worker Nazanin Zaghari-Ratcliffe, who was jailed in Iran in 2016 after being accused of spying, has been temporarily released from prison for three days.
Nazanin Zaghari-Ratcliffe hugs her daughter Gabriella, in Iran.
Although the initial release is for three days her lawyer is hopeful that this can be extended, her husband said.
In a statement issued by the Free Nazanin campaign, Mr Ratcliffe said his wife was given 10 minutes notice on Thursday morning that she was being released until Sunday 26 August.
It is the first time she has been allowed out of prison since her arrest in April 2016 and conviction past year for plotting to overthrow the Iranian regime - something she has always denied. "Nazanin is innocent. She has a 4-year-old daughter Gabriella".
Mrs Zaghari-Ratcliffe "dressed and packed quickly as her cellmates gathered round", the campaign said. She is now with her family in Damavand.
There has been no clear statement from Iranian authorities about why Zaghari-Ratcliffe was released, but some have speculated it could be a conciliatory gesture to mark the Islamic festival of Eid. "But being in prison at all is gross injustice", he said on Thursday.
"This was a very happy surprise after a number of false dawns recently, which had been increasingly unsettling", her husband said.
The campaign thanked "all those involved in making this possible in Tehran and London, and the new foreign secretary".
Former foreign secretary Boris Johnson wrongly claimed that Mrs Zaghari-Ratcliffe had been "teaching journalists" while in Iran despite the fact she had been visiting her parents.
British Foreign Secretary Jeremy Hunt also confirmed her release in a tweet, praising the "tireless campaigning" of her husband and friends.
"I didn't tell Gabriella or for a long time my mum - so if it didn't happen I would be the only one to suffer".
The family was travelling to a family holiday celebration outside of Tehran when they got the news that Zaghari-Ratcliffe would be released.