Nazanin Zaghari-Ratcliffe is expected to be freed from Iran in seven weeks, her family has said, as Britain announced it had stepped up talks on securing her release.
On Sunday Dominic Raab, the foreign secretary, said that the UK has "intensified" negotiations with Iran to release Mrs Zaghari-Ratcliffe, a British-Iranian dual citizen, from "arbitrary detention", adding that they were "pushing very hard" to free her.
Ms Zaghari-Ratcliffe's husband, Richard Ratcliffe, told The Telegraph that he had recently asked the UK government to "seek assurances" from the Iran that she will be released at the end of her sentence and that it won't be the start of a "new game" by the Iranians.
"I think the Government is fully aware of the milestone...it would be very worrying if Nazanin is not allowed to leave at the end of her sentence," said Mr Ratcliffe.
Mr Ratcliffe also wrote to the Iranian embassy in London on January 12 in the hope of ironing out the logistics of her arrival back to the UK in plenty of time. The family has not yet had a response from the embassy, Mr Ratcliffe said, adding that it was "not a great sign".
Details the family were requesting from the Iranians included: when her ankle tag would be removed, whether any exit taxes would need to be paid, the arrangements for returning her passport, and protocol for her travel and check-in arrangements.
The letter noted a reminder to the Iranians that "Nazanin's conviction in 2016 did not include a court-ordered travel ban for a period following her sentence, unlike the restrictions the Revolutionary Court has imposed in the cases of other foreign nationals."
Despite the lack of clarity, "Nazanin is remaining hopeful," her husband said, showing The Telegraph a photo of the calendar that she has made on her wall out of Alice in Wonderland post-it notes, counting down the weeks until her release.
"Freedom" is circled next to March 7. The date she hopes she will be able to fly back to London to be reunited with her husband and six-year-old daughter, Gabriella.
Ms Zaghari-Ratcliffe was released from Iran's notorious Evin prison last year - where she was being held on spying charges that she flatly denies - due to concerns about Covid-19 and has since been under house arrest at her parents' home in Tehran.