The husband of Iranian detainee Nazanin Zaghari-Ratcliffe has criticised Prime Minister Boris Johnson for his “cold decision” to allow Iran to keep “arbitrarily” detaining British nationals.

Richard Ratcliffe, who has been on hunger strike outside the Foreign Office in Westminster for two weeks, said Mr Johnson should use the opportunity of meeting the Iranian delegate at Cop26 to push for the freedom of Britons detained in Evin prison.

On his 14th day of camping in Whitehall, Mr Ratcliffe told the PA news agency he intends to continue the strike until at least the middle of next week.

Richard Ratcliffe
Richard Ratcliffe with his lawyer Penny Madden QC and MP Tulip Siddiq outside the Foreign, Commonwealth and Development Office (Stefan Rousseau/PA)

Ms Zaghari-Ratcliffe has carried our several hunger strikes of her own, the longest of which had lasted 15 days, her husband said.

Surrounded by a small group of relatives and supporters and wrapped in a blanket and hat, he said a candlelit vigil attended by around 70 people the night before had given him a morale boost to keep going.

When asked how he was faring, Mr Ratcliffe said: “I’m feeling a lot flatter, it’s almost as if the batteries are a bit flat.

“As the days go on, the tiredness is a bit more obvious. But I’m still going and still grateful for everyone who’s coming along.”

Mr Ratcliffe, who is being supported by his sister, GP Rebecca Ratcliffe, added: “We have to be careful – the body slowing down is the first sign of pushing too far.

Nazanin Zaghari-Ratcliffe detained
Richard Ratcliffe has gone on hunger strike for the second time in two years (Kirsty O’Connor/PA)

“But it is my intention still to be here when the Iranian delegation are in the UK.

“They are due to come on Sunday so I at least intend on being here until the middle of next week.”

Ahead of the arrival of the Iranian delegate at the Cop26 climate summit in Glasgow, Mr Ratcliffe said he would like Boris Johnson to “take responsibility” and push for his cause.

“It is a cold decision to let the Iranian government keep British nationals hostage, like Nazanin,” he said.

Richard Ratcliffe and his daughter Gabriella
Richard Ratcliffe and his daughter Gabriella in Parliament Square in September (Kirsty O’Connor/PA)

“What I would like him to say to the Iranian delegation is that this can’t go on. We should find a way.

“He’s got an opportunity this week – he should take it.”

Mr Ratcliffe added that his wife “lives in a state of permanent anxiety” in the prison.

Ms Zaghari-Ratcliffe, a British-Iranian dual national, has been in custody in Iran since 2016 after being accused of plotting to overthrow the government.

She had been taking her daughter Gabriella to see her family when she was arrested and was sentenced to five years in prison shortly afterwards, spending four years in Evin Prison and one under house arrest.

According to her family, Ms Zaghari-Ratcliffe was told by Iranian authorities that she was being detained because of the UK’s failure to pay an outstanding £400 million debt to Iran.

Nazanin Zaghari-Ratcliffe detained
Stones with messages beside Richard Ratcliffe outside the Foreign Office in London (Kirsty O’Connor/PA).

The Foreign, Commonwealth and Development Office (FCDO) has said “we are doing all we can” to free Ms Zaghari-Ratcliffe.

A spokesman said: “Iran’s decision to proceed with these baseless charges against Nazanin Zaghari-Ratcliffe is an appalling continuation of the cruel ordeal she is going through.

“Instead of threatening to return Nazanin to prison Iran must release her permanently so she can return home.

“We are doing all we can to help Nazanin get home to her young daughter and family and we will continue to press Iran on this point.”