Talks with Iran to free Nazanin Zaghari-Ratcliffe ‘going up to the wire’ - Boris Johnson
But Mr Johnson, during a trip to the Middle East, was cautious not to elaborate further on the state of negotiations with Tehran “because those negotiations continue to be under way”.
A glimmer of optimism for the 43-year-old came a day earlier when her constituency MP in Hampstead and Kilburn, Tulip Siddiq, said she had been returned her British passport.
Mr Johnson confirmed a British negotiating team was working in Tehran to secure the release of dual nationals, while Mrs Zaghari-Ratcliffe remains at her family home in the Iranian capital.
He told broadcasters at the Emirates Palace hotel in Abu Dhabi "It’s true and has been for a long time that we’re negotiating for the release of our dual nationals in Tehran. Some very sad cases, including Nazanin. I really don’t think I should say much more. I’m sorry.
“Although, you know, things are moving forward. I shouldn’t really say much more right now just because those negotiations continue to be underway and where we’re going right up to the wire.”
Mrs Zaghari-Ratcliffe was arrested in April 2016 as she prepared to fly back to the UK, having taken her daughter Gabriella – then not even two years old – to see relatives.
She was accused of plotting to overthrow the Iranian government and sentenced to five years in jail, spending four years in Tehran’s Evin Prison and one under house arrest.
Both the British Government and Mrs Zaghari-Ratcliffe have always denied the allegations.
While the details of the negotiations remain unclear, it is possible they are linked to a £400 million debt dating back to the 1970s owned to Iran by the UK.
The Government accepts it should pay the “legitimate debt” for an order of 1,500 Chieftain tanks that was not fulfilled after the shah was deposed and replace by a revolutionary regime.
Tehran remains under strict sanctions, however, which have been linked to the failure to clear the debt.