Here is a timeline of the key events since Nazanin Zaghari-Ratcliffe was arrested and sentenced to five years in prison in Iran.
– April 3 2016: The mother-of-one is detained by the Iranian Revolutionary Guard at Imam Khomeini airport after a holiday visit to Iran where she showed her daughter Gabriella to her parents.
– July 12 2016: Richard Ratcliffe, her husband, delivers letters to Downing Street for outgoing prime minister David Cameron and his replacement Theresa May on his wife’s 100th day in custody. He says it is “astonishing” no British minister has publicly criticised Tehran for arresting Mrs Zaghari-Ratcliffe.