Iran has detained yet another dual-national British citizen. What is it hoping to achieve?

With the worrying news that Iranian authorities have again detained another British dual-national, it seems increasingly clear that this tactic is being used in an attempt to apply pressure on European governments.

Kameel Ahmady was arrested at his home in western Iran on Sunday, according to his wife. Ahmady is an anthropologist, working on women’s rights and FGM. Neither British nor Iranian authorities have yet officially commented on his detention, and no ostensible reason has been proffered.

But his detention follows the arrest in July of French-Iranian dual-citizen, Fariba Adelkhah, also an anthropologist, and, of course, the 2016 detention of Nazanin Zaghari-Ratcliffe.

“For years now academics wanting to work on the ground in Iran have had to assess whether or not the topics they are working on are 'safe' to pursue without the spectre of an arrest by the authorities hanging over their head,” says Gissou Nia, a human-rights lawyer and non-resident fellow at the Atlantic Council, focused on Iran.

Whilst operating in more of a grey area than human rights activists and journalists, Nia cautions that it “is increasingly apparent that pursuing even what is seemingly a benign field of study can put you at risk”.

Inescapably, though, Ahmady’s arrest comes at a time of heightened tensions between the UK and Iran, never the best of friends. (Zaghari-Ratcliffe’s detention has also been linked to the 1970s debt that Tehran wants repaid, after it bought £400m of tanks and armoured vehicles from Britain, the delivery of which was reneged on after the Shah was deposed in the 1979 Islamic Revolution.)

The current nadir in relations follows tit-for-tat seizures, starting with British Royal Marines detaining an Iranian oil tanker, the Grace 1, allegedly headed for Syria, in violation – according to the UK – of EU sanctions. Iran has denied the ship was going to Assad’s regime. And then came the apparent response, when Iranian Revolutionary Guard commanders boarded and detained a UK-flagged vessel, the Stena Impero.

These developments themselves come amid increasingly tense rhetoric between Tehran and Washington DC, following Donald Trump’s departure from the historic 2015 Joint Comprehensive Plan of Action – the Iran nuclear deal which took years of diplomacy, and, bt everyone else’s accounts, was successfully keeping Tehran from building an atomic weapon.

With the subsequent heaping on of sanctions against Iran by the US, authorities in Tehran appear increasingly frustrated. And while Iran officially does not recognise dual-nationals, authorities there appear perfectly happy to use them as bartering chips.

As Holly Dagres, curator of the Iranist.com website, says: “This latest arrest is likely another attempt to use dual nationals as pawns in Iran’s dealings with the west.”

And with Boris Johnson agreeing to enter into a US-led maritime coalition in the fractious Strait of Hormuz – contrary to earlier suggestions the UK would be entering into a less provocative EU-led force – tensions between London and Tehran are unlikely to cool down any time soon.