In Pictures: The battle to free Nazanin Zaghari-Ratcliffe

Here is a look back at the key events.

The ordeal of detained British-Iranian mother Nazanin Zaghari-Ratcliffe may be a step closer to ending after her passport was returned, sparking hopes she will be freed by authorities in Iran.

Her MP Tulip Siddiq also tweeted that a British negotiating team is in Tehran.

Mrs Zaghari-Ratcliffe was arrested in 2016 on charges of plotting to overthrow the government during a visit to her parents with her young daughter Gabriella – allegations she has always denied.

Here is a look back at key events over the past six years.

Nazanin Zaghari-Ratcliffe detained — A vigil was held outside the Iranian Embassy in Kensington, central London, for Nazanin Zaghari-Ratcliffe in 2017 (Kirsty O’Connor/PA)