Jailed British mother Nazanin Zaghari-Ratcliffe has been asked by the country’s Revolutionary Guard to spy against Britain to secure her release from a Tehran jail, her husband has said.

The revelation is believed to have prompted foreign secretary Jeremy Hunt to summon the Iranian ambassador for an urgent meeting on Monday afternoon.

The approach by two interrogators has left the British charity worker “terrified”, Richard Ratcliffe said.

He said she was asked to spy on Britain’s Department for International Development (Dfid).

Monday’s revelation comes on the same day that Ms Zaghari-Ratcliffe, 40, began a hunger strike about the alleged refusal to grant her proper access to medical treatment while she is held in Evin Prison, Tehran.

Mr Ratcliffe told a press conference that he was also due to speak later on Monday to Mr Hunt in order to press him to grant the jailed British charity worker legal “diplomatic protection” status that might allow the UK to intervene more strongly in her case.

On social media, Mr Hunt described Ms Zaghari-Ratcliffe’s continued detention in far from diplomatic terms, calling it “totally unacceptable” and “a fundamental breach of human rights”.

Mr Ratcliffe said the approach made on December 29 by two Revolutionary Guard interrogators was “simply outrageous”.

“They tried to pressure her to be a spy for Iran, spying on Dfid and [anti-censorship NGO] Small Media,” he said. “They told her it would be safer for her and her family if she agreed to do this.”

In a transcript of Nazanin’s account of the conversation with the interrogators, Mr Ratcliffe and his supporters said that one interrogator had moved towards suggesting she spy on the UK government by saying: “Maybe you can help us? What do you know about UK Aid and Dfid? And what do you know about Small Media?”

When she furiously refused to be a Revolutionary Guard “agent”, the transcript says, one of the interrogators replied: “Have a think about it.”

The two men said they would come back to see her again.

Husband of Nazanin Zaghari Ratcliffe gives Christmas update on British charity worker jailed Iran

Ms Zaghari-Ratcliffe was enraged, and relayed the message to her husband: “How dared they ask that – at the end of all this?”

Mr Ratcliffe said: “She came out of that conversation terrified, and in no doubt that she had been warned that the only way she would get out [of jail] would be if she agreed to become a spy.”

This pressure was seemingly applied despite the Iranian authorities and state media having demonised her as a British “spy” ever since she was arrested in Tehran in April 2016 when trying to return to London after a holiday with her then 21-month-old daughter Gabriella.

Her incarceration has been widely condemned as “a travesty of justice”, but the British government’s handling of her case became hugely controversial in November 2017 when the then foreign secretary Boris Johnson accidentally and wholly erroneously bolstered the Iranians by saying the dual-national had been teaching journalists in Iran.

In fact the charity worker has never worked as, or trained journalists in her life. She had been visiting Iran to spend time with her parents, who were also keen to see Gabriella, their granddaughter.

Mr Ratcliffe has previously said that his wife’s treatment at the hands of her captors had amounted to “torture” and had left her feeling suicidal.

Ms Zaghari-Ratcliffe and her cellmate, the jailed Iranian human rights activist Narges Mohammedi have gone on hunger strike to demand that they be allowed to attend appointments with medics, and that they receive a written commitment that this will not just be a single token visit to a doctor.

Ms Zaghari-Ratcliffe is demanding medical treatment to check lumps found in her breasts, neurological care for her neck pains and numbness in her arms and legs, and access to an outside psychiatrist.

The current plan is to limit her protest to three days in the hope the Iranian authorities will have responded positively by then, but Mr Ratcliffe said he was worried about whether his wife had the physical and mental strength to withstand a hunger strike.

“A hunger strike of three days is a completely different thing to one that she decides to extend. At the moment, I am calm, but if she decides to extend the hunger strike, I will panic.”

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A Foreign Office spokesman said: “The foreign secretary will call for Nazanin to be immediately given the healthcare she requires and for her and other innocent British Iranian dual nationals to be released.

“We have repeatedly lobbied the Iranians to release Nazanin on humanitarian grounds and we will continue to raise all our cases at every level and every opportunity.”