Nazanin Zaghari-Ratcliffe's husband has said an "important lifeline has been taken away" as their five-year-old daughter arrived back in the UK after spending nearly four years in Iran.
Speaking to reporters hours after five-year-old Gabriella arrived, Richard Ratcliffe said his wife is "really upset", adding it was a "real risk" her mental and physical condition would deteriorate.
Gabriella had been living in Iran with her grandparents, visiting her British-Iranian mother in a Tehran jail.
Mrs Zaghari-Ratcliffe has been serving a five-year prison sentence on spying charges in the notorious Evin Prison since 2016. She vehemently denies the allegations.
Mr Ratcliffe, who has been campaigning for her release from the UK, said it has been a "rollercoaster" since he was told his daughter may be allowed to return.
"(Nazanin's) really upset, really upset, one of the things that she didn’t want to happen is for her daughter to leave and for her to be still stuck in prison.
"So it's been a turmoil of feelings."
Gabriella sat on her father's lap as he spoke to media about how "lovely" it's been to have her back in his arms.
The five-year-old cut up some "celebration" cake before eating a piece while her father spoke to media.
He said she was "a bit shy, a bit traumatised, she hasn’t seen daddy in a long time," adding "It takes her a while to feel safe."
Mr Ratcliffe said Gabriella has been "very brave".
"She's told mummy that she will see her back in London," Mr Ratcliffe said.
"She's promised mummy she's going to be brave.
"It's just lovely to hold her again."
Mr Ratcliffe also told reporters he wants to meet with Prime Minister Boris Johnson.
"We have been caught in the middle of a gun fight," he said.
"We will be looking to meet with Boris as soon as possible.
"This is an area where he can make a difference.
"He took responsibly for it as foreign secretary... he hasn't yet delivered for us."
His comments followed Tuplip Sidiq MP calling for the UK to pay Iran the debt it is "legally owed" to secure Mrs Zaghari-Ratcliffe's release.
Former foreign secretary Jeremy Hunt also called for more to be done as he shared the image of Gabriella being reunited with her father, adding: "This must be the definition of bittersweet. Govt must redouble efforts to bring Nazanin home. Now more than ever, she needs to know she's not alone. #freenazanin."
