Key events since the arrest of Nazanin Zaghari-Ratcliffe in Iran

Here is a timeline of the key events since Nazanin Zaghari-Ratcliffe was arrested and sentenced to five years in prison after being accused of spying.

- 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.

- August 9 2016 - New Prime Minister Mrs May "raised concerns" about Mrs Zaghari-Ratcliffe during a phone call with President of Iran Hassan Rouhani.

- September 9 2016 - Mr Ratcliffe says his wife has been jailed for five years following a conviction on unspecified "national security-related" offences- a sentence he describes as "a punishment without a crime".

- November 13 2016 - Mrs Zaghari-Ratcliffe begins a hunger strike which she ends after five days amid her family's fears for her health.

- January 2 2017 - Mr Ratcliffe says Mrs May and her ministers could have "publicly stood up for Nazanin more" and should have called for her release. Mr Ratcliffe said: "She raised those concerns in September. What happened after September? Nothing much, really."

- April 24 2017 - The family of Mrs Zaghari-Ratcliffe say she has lost the final stage of her appeal against the sentence.

- November 6 2017 - It is feared Mrs Zaghari-Ratcliffe may face a further period of imprisonment because of remarks made by Foreign Secretary Boris Johnson. Mr Johnson told a parliamentary committee the previous week that Mrs Zaghari-Ratcliffe was working in Tehran training journalists at the time of her arrest in 2016. Four days later, she was summoned before an unscheduled court hearing, where
the Foreign Secretary's comments were cited as proof that she was engaged in "propaganda against the regime."

- November 7 2017 - It is announced that Mr Johnson told his Iranian counterpart in a phone call that his comments to a Commons committee provide "no justifiable basis" for further legal action against Mrs Zaghari-Ratcliffe. A Foreign Office spokesman says Mr Johnson now accepts that he "could have been clearer" when he told the Foreign Affairs Committee that the British woman had been training journalists in Iran at the time of her arrest.

- November 12 2017 - Mr Ratcliffe says his wife has seen a medical specialist after finding lumps on her breasts and is "on the verge of a nervous breakdown".

- November 15 2017 - Mr Ratcliffe describes an hour-long meeting with Mr Johnson as "positive and constructive".

- December 12 2017 - Mr Johnson said he and his Iranian counterpart spoke "frankly" regarding the case of Mrs Zaghari-Ratcliffe, during talks in Tehran.

- Later in December 2017 - Mr Ratcliffe said he believes there is "still a chance" his wife may be released in time for a dream Christmas together.

- December 28 2017 - Mr Ratcliffe says he is in limbo waiting for news of his wife's release but has not given up hope, and describes the situation as "a lot more positive" than last year.

- April 14 2018 - Iranian ambassador to the UK, Hamid Baeidinejad, says the Iranian government is doing its best to secure Mrs Zaghari-Ratcliffe's release, saying the judicial process was "complicated" but insisted "we are trying our best".

- May 21 2018 - Mr Ratcliffe says his wife has been told to expect another conviction after appearing in court over a new "invented" charge.

- August 3 2018 - New Foreign Secretary Jeremy Hunt pledges to do everything possible to secure Mrs Zaghari-Ratcliffe's release, after talks with Mr Ratcliffe.

- August 21 2018 - Mr Hunt says he is considering a request by Mrs Zaghari-Ratcliffe's husband to grant her diplomatic protection.

- August 23 2018 - Mrs Zaghari-Ratcliffe is given temporary release from prison for three days and her husband says it feels like "home is one step closer".