Nazanin Zaghari-Ratcliffe and husband launch joint hunger strike in protest over her imprisonment in Iran

Incarcerated charity worker Nazanin Zaghari-Ratcliffe has begun a fresh hunger strike in prison, her husband said today.

Richard Ratcliffe, who said her demand from the move was for unconditional release, said he would also conduct his own hunger strike to coincide with his wife's protest.

He plans to start the "open-ended" strike during a vigil outside the Iranian Embassy in London today.

He said the pair had decided to take joint action if nothing had changed by their daughter Gabriella's fifth birthday.

Mr Ratcliffe said: "Today I received a phone call from Nazanin in prison. She had informed the judiciary that she has begun a new hunger strike (she will drink water) to protest at her continuing unfair imprisonment.

"This is something she had been threatening for a while. 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.

"Today she sounded nervous, but calm. Her demand from the strike, she said, is for unconditional release. She has long been eligible for it."

Mr Ratcliffe said he will begin a continual vigil outside the Iranian Embassy from midday on Saturday.

He said: "We were planning a small event in front of the Iranian Embassy to mark Gabriella's birthday - I remember marking her second birthday there while we didn't even know where Nazanin was, and now here we are marking her fifth.

"Given Nazanin's decision, later today I will also begin a continual vigil in front of the Iranian Embassy, perhaps occasionally joined by friends and family.

"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."

In an interview with Sky News, Mr Ratcliffe said this strike is a bit more "open ended" than her previous two.

"I'm hoping its not going to last weeks and weeks and weeks," he said.

He added that while his wife's physical health had been assessed as relatively fine - lumps in her breasts were benign and neck problems could be treated with physiotherapy - her mental health was "really bad".

"The doctor said she should be hospitalised immediately, which hasn't yet happened," he said.

Mrs Zaghari-Ratcliffe was arrested on April 3 2016 at Tehran's Imam Khomeini Airport 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 Tehran's notorious Evin Prison.

Foreign Secretary Jeremy Hunt granted Mrs Zaghari-Ratcliffe diplomatic protection in March, but Tehran refuses to acknowledge her dual nationality.

Kate Allen, director of Amnesty International UK, said the decision to go on another hunger strike was a "truly heartbreaking situation".

"Nazanin has already been through so much, while her tireless husband Richard has strained every sinew to get Nazanin out of jail and back to the UK where she belongs," she said.

"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.

"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."