LONDON -- Richard Ratcliffe calls what Iran is doing “hostage diplomacy.” He has been on a hunger strike for 12 days. Camped outside the Iranian Embassy in London, his message is simple: His wife, Nazanin Zaghari-Ratcliffe, must be freed.

Nazanin was arrested while visiting her mother with her then 2-year-old daughter in Tehran three years ago and ultimately convicted of trying to overthrow the regime, charges her family calls false. They believe she is nothing but a bargaining chip.

“I think it’s quite important,” Ratcliffe told Fox News, “that the U.S., the U.K. and other allies work together, with private diplomacy, and also at the UN. We can all take each other’s citizens hostage as bargaining chips. But that’s no way to solve issues. And people just need to be safe.”

It was Nazanin who called the hunger strike, out of desperation. Ratcliffe followed in solidarity. He said Iran has stepped up the pressure on her since. She was able to call him over the weekend.

HUSBAND SAYS BRITISH WOMAN HELD IN IRAN BEGINS HUNGER STRIKE

“She was pretty traumatized,” Ratcliffe began. “She was being pressured by the Revolutionary Guard at that point to end the hunger strike. Their job is to be scary. They certainly are. This is day 12 of our hunger strike. It’s tough for me and I’m sure it’s much tougher for her.”

Also tough is the fact that Ratcliffe hasn’t seen his daughter Gabriella for three years, apart from Skype calls. She is being looked after by her maternal grandparents in Tehran and not allowed to leave the country. Neither parent is there for her as they want to be, as she grows up. Gabriella’s weekly visit to her mother in Iran’s notorious Evin Prison was canceled after the hunger strike began.

FILE -- In this Jan. 16, 2017 file photo, Richard Ratcliffe, husband of imprisoned charity worker Nazanin Zaghari-Ratcliffe, poses for the media during an Amnesty International led vigil outside the Iranian Embassy in London. The family of Zaghari-Ratcliffe who was detained in Iran while on a trip with her toddler daughter says all efforts to appeal her five-year prison sentence in court have failed. Ratcliffe, who works for the Thomson Reuters Foundation, the charitable arm of the news agency, found out this weekend that her appeal to Iran's supreme court failed. (AP Photo/Alastair Grant, File)

FILE -- In this Jan. 16, 2017 file photo, Richard Ratcliffe, husband of imprisoned charity worker Nazanin Zaghari-Ratcliffe, poses for the media during an Amnesty International led vigil outside the Iranian Embassy in London.  (The Associated Press)

Ratcliffe was expecting to hear from Nazanin Wednesday, but there was no news.

DETAINED IRANIAN-BRITISH WOMAN LEARNS OF NEW CHARGES IN IRAN

Ratcliffe said her health is fragile and her mental state more so. Nazanin works for the Thomson Reuters Foundation, the charity arm of the news organization, as a project manager. In an apparent slip, former Foreign Secretary Boris Johnson falsely said in 2017 that she was training journalists in Iran.  It has been a slip that Nazanin’s family says has cost her dearly, giving fuel to Iranian accusations of espionage, saying that was essentially proven by the British government. Nazanin’s employer says she is not a journalist and does not train journalists.

Well-wishers have been coming by Ratcliffe’s encampment, leaving cards and flowers. Ratcliffe said that has meant very much to him. He said most of the flowers were left by Iranians, some of whom shared their own personal stories and expressed shame at what their country had done.

A British Minister Foreign Office Minister visited Iran earlier this week and raised Nazanin’s case. Apparently, his appeal fell on deaf ears.

An Iranian Foreign Ministry spokesman said, “Mrs. Zaghari is an Iranian. She has been convicted on security charges and is spending her sentence in prison.”

CLICK HERE TO GET THE FOX NEWS APP

Others have called the hunger strikes a sort of blackmail, something Ratcliffe called ironic, “since I am not the one who is holding an innocent person as diplomatic leverage.”

UK Foreign Minister Jeremy Hunt, addressing Parliament the other day, said of Ratcliffe:

“He’s doing a remarkable job and I know the whole House is thinking about Nazanin, thinking about her 5-year-old daughter, thinking about that family and our message to Iran is very simple—whatever disagreements you have with the UK, do not punish this innocent woman. It’s not her fault. Let her come home.”

That is something Ratcliffe can hardly wait for. When asked, he was happy to describe the woman who Amnesty International calls “a prisoner of conscience.”

“She is kind and creative, playful and jubilant with this sort of really infectious sense of exploring the world. We had some very happy years together.  We will have some happy years again,” he said. “My job is to keep her knowing home is waiting for her.”