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.

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

During her detention, family and friends in the UK have long campaigned for her freedom.

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In April 2017, her husband Richard Ratcliffe, tied ribbons and messages of support to a tree in Fortune Green, West Hampstead, to mark 365 days since his wife was imprisoned in Tehran (Gareth Fuller/PA)
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In November 2017, then-foreign secretary Boris Johnson met with Mr Ratcliffe at the Foreign and Commonwealth Office (Stefan Rousseau/PA)
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Mrs Zaghari-Ratcliffe with her daughter Gabriella in 2018 while Gabriella was living with her grandparents in Tehran (Free Nazanin campaign/PA)

Mr Ratcliffe has gone on hunger strikes as part of the campaigns to raise awareness of his family’s plight.

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In 2019, Mr Ratcliffe started a hunger strike outside the Iranian Embassy (Jonathan Brady/PA)
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Letters of support sent to Mr Ratcliffe as his hunger strike entered its eighth day (Victoria Jones/PA)
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Gabriella standing next to her father and his mother Barbara as they addressed the media in Downing Street following a meeting with Prime Minister Boris Johnson after her return from Tehran (Stefan Rousseau/PA)
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Mr Ratcliffe and his daughter during a protest outside the Iranian Embassy in London in March 2021 (Ian West/PA)
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Father and daughter after the five-year-old returned to the UK in 2019 so she could attend school (Victoria Jones/PA)

The mother-of-one has scarcely seen her daughter throughout her ordeal. After three years with her grandparents, Gabriella, then aged five, was allowed to return to her father in the UK in October 2019.

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The pair holding signs in Parliament Square, London, to mark the 2,000th day Mrs Zaghari-Ratcliffe had been detained in Iran in September 2021 (Kirsty O’Connor/PA)
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Mr Ratcliffe went on hunger strike for the second time in two years in late 2021, sleeping in a tent at night following his wife losing her latest appeal in Iran (Aaron Chown/PA)
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Mr Ratcliffe spent 21 days camped outside the Foreign, Commonwealth and Development Office (FCDO) in London without food (Aaron Chown/PA)