Campaigners battling to free jailed Hampstead mum Nazanin Zaghari-Ratcliffe have called on supporters to join them in a carol singing vigil outside Downing Street.

Ham & High: Emma Thompson speaks at the Mothers March for Nazanin on Saturday, November 25. Picture: POLLY HANCOCKEmma Thompson speaks at the Mothers March for Nazanin on Saturday, November 25. Picture: POLLY HANCOCK (Image: Archant)

Nazanin’s husband Richard Ratcliffe will be joined by a group of British men acquitted of weapons charges and freed on Tuesday after spending four years in an Indian prison.

The ex-servicemen known as the Chennai six were working as security guards on an anti-piracy ship when they were detained in 2013. They are due to share messages of hope with Free Nazanin campaigners yards away from Number 10.

Ham & High: Ham&High editor Emily Banks and Richard Ratcliffe talk to Nazanin on the phone during the rally. Picture: POLLY HANCOCKHam&High editor Emily Banks and Richard Ratcliffe talk to Nazanin on the phone during the rally. Picture: POLLY HANCOCK (Image: Archant)

Nazanin, 38, of Fortune Green Road, was seized at Tehran airport in April last year along with her daughter Gabriella as they tried to return to the UK from a family holiday.

In August 2016 the charity worker was sentenced to five years behind bars after a judge in a secret trial found her guilty of plotting against the Iranian regime.

Ham & High: A Hampstead march to Free Nazanin in December last year led by Jessica Learmond-Criqui. Picture: POLLY HANCOCKA Hampstead march to Free Nazanin in December last year led by Jessica Learmond-Criqui. Picture: POLLY HANCOCK (Image: Archant)

Nazanin, who has suffered insomnia, depression and panic attacks as a result of her imprisonment, now faces being dragged back to court for a second trial which could see her sentence extended.

The carol singing vigil takes place on Tuesday, December 5 from 5.30pm in Richmond Terrace opposite Downing Street.