A British-Australian academic is still being held in Iran while another British-Australian woman and her Australian boyfriend have been released from detention.

Tehran has pursued a campaign of detaining Iranian and dual nationals academics in recent years, raising fears the Islamic republic is using them as diplomatic leverage.

While there are no exact figures on the number of detainees with British links being held in Iran, these are at least some of those who are understood to be incarcerated as part of Iran's "hostage diplomacy".

Jolie King

Ms King was camping with her Australian fiance Mark Firkin near a military site in Jajrood near Tehran when the pair were arrested by the Revolutionary Guard on August 9 for reportedly flying a drone without a licence.

The couple, who live in Perth, Western Australia, had been travelling across Asia for months, chronicling their journey regularly on YouTube and Instagram.