Fears are growing for the welfare of jailed British-Iranian mother Nazanin Zaghari-Ratcliffe, who is to have access to her five-year-old daughter restricted, according to her family.

New rules at the Iranian prison where she is being held also mean she is unable to speak to her British husband Richard Ratcliffe.

The 40-year-old was arrested in April 2016 and sentenced to five years imprisonment after being accused of spying, which she vehemently denies.

Last night the Free Nazanin campaign, which is spearheaded by her husband, tweeted of the new restrictions.

It said: “New rules have been issued for Nazanin’s ward restricting children visits to only once a month as part of the wider family and preventing international calls.

“This means Nazanin can only see Gabriella once a month and can no longer speak to Richard.”

Gabriella lives in Iran with her grandparents and according to reports has previously been allowed to visit her mother regularly during the week.

Ratcliffe told the BBC his wife has written to the Iranian prison authorities to protest against the changes.

“The phone calls is one thing but not being able to see Gabriella… that’s really tough”, he said.

He added: “Boris Johnson, when he was foreign secretary, made a clear promise to leave no stone unturned we want to hold him to that promise.”

In a much-criticised error, now Prime Minister Johnson said in 2017 that she was in Iran “teaching people journalism” – despite her family’s insistence she was there to visit relatives.

He has repeatedly said the responsibility for her continued detention lies with the Revolutionary Guard.

Human rights charity Amnesty International said it was “devastated” to hear the news that Zaghari-Ratcliffe is having access to her family curtailed. It tweeted: “We hope that Dominic Raab will meet Richard Ratcliffe as a matter of urgency to end this injustice and do all he can do.”

Foreign Secretary Jeremy Hunt earlier this year granted Zaghari-Ratcliffe diplomatic protection in an attempt to resolve her case.

The mother’s fight for freedom has seen her endure hunger strikes, separation from her daughter and solitary confinement, amid the major diplomatic row.

Last month, Zaghari-Ratcliffe was transferred back to Evin prison after a spell in a hospital mental-health ward, which she described as “proper torture.”

According to her husband she was kept in solitary confinement was chained to her hospital bed.

But she was returned to prison after breaking out of her bindings and telling security guards she was at risk of self-harming if she remained in the hospital, Ratcliffe said. He said his wife told him she was “broken” by the experience and was “relieved” to be back in prison.

Zaghari-Ratcliffe’s admission to the mental health unit came after she went on hunger strike for 15 days in June in protest against her “unfair imprisonment”.

Her husband joined the hunger strike in solidarity, and camped on the pavement outside the Iranian embassy in London.