Theresa May will tomorrow personally lobby the president of Iran to release the British mother imprisoned by the regime.
Aid worker Nazanin Zaghari-Ratcliffe was sentenced to five years in prison in 2016 after being accused of spying by Tehran’s Islamist regime.
Mrs May will use a one-on-one meeting with President Hassan Rouhani to urge him to release her.
Aid worker Nazanin Zaghari-Ratcliffe was sentenced to five years in prison in 2016. She was briefly reunited with her daughter last month
The two leaders are due to meet this evening at the United Nations General Assembly in New York.
A senior Government official said Mrs May would express ‘serious concerns’ at Mrs Zaghari-Ratcliffe’s ongoing detention and call for her to be released on humanitarian grounds.
The move marks an escalation of the Government’s campaign on behalf of the mother-of-one, who has joint British and Iranian citizenship, and will increase the pressure on Iran to let her out.
It follows intensive diplomatic efforts from Foreign Secretary Jeremy Hunt, which last month saw Mrs Zaghari-Ratcliffe granted temporary release.
She spent three days with her family, reuniting with her four-year-old daughter Gabriella. She was quoted as saying she ‘cried so much’ and said she wanted her child to ‘have a mummy again’.
But she was then forced back to jail and a few days later she was taken to hospital after suffering panic attacks in her cell.
The senior government official said: ‘Clearly our thoughts remain with Nazanin and with her friends and family who have campaigned tirelessly for her release. Our consular cases in Iran, including that of Nazanin, remain a top priority for this Government.’
During her two days in New York, Mrs May is also expected to meet US President Donald Trump for the first time since he came to Britain this summer.
The two leaders are set to discuss prospects for a post-Brexit US-UK trade deal.
The Prime Minister will also raise the issue of chemical weapons worldwide following the novichok attack in Britain.
In her address to the General Assembly, Mrs May will warn that ‘red lines’ around chemical weapons are being ‘eroded’.
She will point to the ‘despicable’ use of novichok by Russia in Salisbury and by the Syrian regime against its own people.
Mrs May will say: ‘The Syrian regime has repeatedly used these appalling weapons against its own people while the Russian state has deployed them on UK streets. Attacks such as Salisbury and Ghouta are despicable in their own right, but they are also a threat to the wider international system.
‘Each time we fail to challenge the use or development of weapons of mass destruction it erodes the framework of treaties we have built up so painstakingly over the past few decades.’ She will urge the international community to ‘do more together to prevent future chemical weapons use and ensure those who use them are held to account’.
Mrs Zaghari-Ratcliffe has consistently denied all the spying allegations, insisting that she was on holiday to introduce Gabriella to her family.
Mr Hunt’s predecessor, Boris Johnson, was accused of extending her sentence after mistakenly describing her as a journalist who was working on her trip.