Nazanin Zaghari-Ratcliffe – the British-Iranian mother jailed in Iran on spying charges – has begun a new hunger strike, her husband has said.

Richard Ratcliffe said he had received a phone call from his wife to tell him she had informed the Iranian judiciary she had stopped taking food in protest at her “unfair imprisonment”.

Mr Ratcliffe has since begun his own strike, outside the Iranian embassy in Knightsbridge, London, in solidarity with his wife.

He told the Press Association: “(Nazanin) has been on hunger strike before, it achieved something but not much.

“I said that if she did it again I would stand in solidarity with her.

“A hunger strike in prison, nobody gets to see it, a hunger strike here is much more public.

“I will keep her story public.”

In a direct message to the future British prime minister, Mr Ratcliffe said: “It’s really important to protect British citizens from being held unfairly, innocent and abroad.

“I want whoever becomes prime minister, one of their top priorities is to make sure they protect British citizens from unfair imprisonment, from torture, from the horrible stuff.

“Make this a part of your premiership.”

Foreign Secretary Jeremy Hunt, who is among those battling for the keys to No 10, said: “As Richard continues his campaign for Nazanin’s release at the Iranian embassy,my message to Iran: DO THE RIGHT THING, SHOW THE WORLD YOUR HUMANITY & LET THIS INNOCENT WOMAN HOME #freenazanin”

Richard Ratcliffe
Richard Ratcliffe outside the Iranian Embassy in London where he is on hunger strike (Jonathan Brady/PA)

Mr Ratcliffe said his wife’s decision followed the fifth birthday of their daughter, Gabriella, who has not been allowed to leave Iran following her mother’s arrest in 2016 and is living with her grandparents.

“This is something she had been threatening for a while,” Mr Ratcliffe said.

“Nazanin had vowed that if we passed Gabriella’s fifth birthday with her still inside, then she would do something – to mark to both governments that ‘enough is enough’.

“This really has gone on too long.”

Mr Ratcliffe said his wife sounded “nervous but calm” when she spoke to him from prison.

“Her demand from the strike, she said, is for unconditional release,” he said.

“She has long been eligible for it. I do not know the response from the Iranian authorities.”

Mr Ratcliffe said he had previously been planning a “small event” outside the Iranian embassy in London to mark Gabriella’s birthday.

“Given Nazanin’s decision, I will also begin a continual vigil in front of the Iranian embassy, perhaps occasionally joined by friends and family,” he said.

“During this vigil I will also not eat and will continue this fast until such time as her hunger strike ends.

“I vowed last time that if she ever went on hunger strike again, we would not leave her to go through this ordeal alone.”

He said he would not put a time limit on his fasting.

Mrs Zaghari-Ratcliffe was arrested on April 3 2016 at Imam Khomeini Airport in Tehran as she prepared to board a plane with Gabriella back to the UK after visiting relatives.

The 40-year-old is serving a five-year sentence in the notorious Evin Prison.

Mr Hunt granted Mrs Zaghari-Ratcliffe diplomatic protection in March but Tehran refuses to acknowledge her dual nationality.

In January, she refused food for three days in protest at the decision of the prison authorities to deny her access to medical treatment.

Mr Ratcliffe, who is calling for his wife’s immediate release, urged the Iranian authorities to allow British embassy officials to visit her to check on her health.

Nazanin Zaghari-Ratcliffe with her daughter
Nazanin Zaghari-Ratcliffe, holding her daughter Gabriella (The Free Nazanin campaign/PA)

He said if she was not freed within the next few weeks, he wanted the Iranians to grant a visa so he could visit her himself.

Amnesty International UK’s director Kate Allen said her plight was “truly heartbreaking”.

“Nazanin is a prisoner of conscience, unfairly jailed after a sham trial and subjected to all manner of torments – including months in solitary confinement and endless game-playing over whether she would receive vital medical care,” she said.

“It’s shocking that it’s come to this and we and countless people across the country fervently hope the Iranian authorities will now finally do the right thing and release Nazanin.”