Iranian authorities have arrested two British nationals on security-related charges.

       According to Iranian state media, the man and woman - who have not been named - are in custody in Iran's southeastern city of Kerman.

       Iran's official news agency published blurred images of the two meeting with British ambassador Hugo Shorter in a courtroom in Kerman, but did not identify them.

       It was not clear when they were originally detained.

       According to an Iranian media report: "So far, no information has been published about the exact charges of these two British citizens, their judicial process and the circumstances of the meeting.

       "Judges in Kerman have announced that more details of this case will be published in the future through official media.”

       The report adds: “Cases related to security crimes are highly sensitive and any action in this field may have diplomatic and political dimension.”

       Iran’s nefarious Islamic Republican Guard Corps has often arrested foreign nationals or those with dual citizenship on trumped up security charges as a way to win concessions from other nations.

       In 2016, charity worker Nazanin Zaghari-Ratcliffe’s was accused of spying - charges she has strongly denied - and imprisoned for six years.

       Her ordeal was only ended in 2022 when the UK settled a long-standing debt of ￡400m for 1,300 Chieftain tanks ordered and paid-for by the Shah of Iran, but not sent to the country following the Islamic Revolution which toppled him.

       Charging the couple with national security violations such as treason and espionage will, experts say, open the door to more backchannel negotiations with the British Government.

       One area of particular interest for Tehran is the resumption of nuclear talks.

       Despite the US’ withdrawal, Britain, Germany and France are still technically engaged with the JCPOA nuclear deal, which is due to expire in October. With that comes the resumption of heavy UN sanctions.

       “This is a relatively routine practice for Iran when it comes to dual and foreign nationals. Effectively, the security forces will arrest nations from particular states and leverage their detention to gain broader concessions from that state,” said regional expert Megan Sutcliffe from the Sibylline strategic risk group.

       “We saw this a few months ago with the arrest of an Italian journalist - Iran freed her and four days later, Italy freed an Iranian prisoner.

       "We also see the same thing following vessel seizures, sanctions enforcement.”

       She added: “Backroom chats with the British Government could relate to frozen assets or high value Iranian prisoners.

       “It is also likely designed to increase pressure on the E3 - the UK, Germany and France - to resume E3 nuclear negotiations.

       "The deal is set to fully expire in October of this year, bringing back sanctions under UNSCR 2231 - which would be deleterious for an Iranian economy already under significant pressure from US President Donald Trump's maximum pressure policies."

       The FCDO was contacted for comment.