The sentence of a British mother detained in Iran is due to come to an end today after nearly five years.

British-Iranian dual national Nazanin Zaghari-Ratcliffe, 42, has been held in Iran since 2016, when she was sentenced to five years in prison over allegations, which she denies, of plotting to overthrow the Iranian government.

She was arrested at Tehran’s Imam Khomeini airport while travelling to show her young daughter to her parents in April 2016.

Sunday March 7 marks the day when her sentence is scheduled to come to an end.

Mrs Zaghari-Ratcliffe’s husband Richard and daughter Gabriella – who is now of school age – are  waiting to find out whether they will be reunited at home in north London.

Mr Ratcliffe previously told the PA news agency that Gabriella was counting down the days until her mother returned.

He explained: “She’s got a calendar that she crosses off each day – yesterday she did two by mistake, so we had to tell her that she can’t do one today.

“She’s in that sense counting down and I think probably still at this point treating it like an advent calendar, so the days will come off and then the magic delivery will happen.”

Mr Ratcliffe added: “She’s been asking: ‘When’s mummy coming back, when’s mummy coming back?’ Hopefully this won’t be tough for her psychologically if mummy doesn’t come back at the end of all those days on the calendar.

“She’s had a lot of experience of grown-ups promising her that mummy’s coming home and then mummy not coming home.”

Mrs Zaghari-Ratcliffe has been out of prison since last spring due to the coronavirus crisis, but has been held under house arrest at her parents’ house in Tehran.

Mr Ratcliffe said: “It is shocking that what started off as a mum and a baby on holiday could be allowed to last for five years.

“There’s no ambiguity in that, that’s just staggering,” he added.

The Foreign, Commonwealth and Development Office said in a statement: “The Foreign Secretary and FCDO remain in close contact with Zaghari-Ratcliffe and her family, and continue to provide our support.

“We do not accept Iran detaining dual British nationals as diplomatic leverage. The regime must end its arbitrary detention of all dual British nationals.

“We continue to do everything we can to secure the release of arbitrarily detained dual British nationals so that they can be reunited with their loved ones.”