A British-Australian academic being held in jail in Iran has gone on hunger strike after an appeal against her sentence failed.

Kylie Moore-Gilbert has been behind bars in Iran’s most notorious prison for more than a year, after being sentenced to 10 years on spying charges, which she vehemently denies.

The university lecturer, together with Fariba Adelkhah, a French-Iranian researcher, started refusing food and water on Christmas Eve, both protesting their innocence.

The Evin prison in Tehran, where they are being held, has a reputation for brutal treatment of inmates, including mock executions, beatings and psychological torture.

The US-based Center for Human Rights in Iran (CHRI) said the women were in a ward run by the Islamic Revolutionary Guard, where British-Iranian charity worker Nazanin Zaghari-Ratcliffe has also been detained.

Like at least nine other foreigners jailed in Iran, the women claim they are being held on trumped-up charges, the group says. In an open letter, the pair state that they have been subjected to psychological torture and human-rights violations.

Ms Moore-Gilbert, a Cambridge graduate and lecturer in Islamic studies at the University of Melbourne, has written about revolutions and activism in the Middle East.

Her appeal against her 10-year sentence – a common term for spying – failed last week.

She has been kept in solitary confinement for much of her time.

Nazanin Zaghari-Ratcliffe – in pictures Show all 20 1 /20 Nazanin Zaghari-Ratcliffe – in pictures Nazanin Zaghari-Ratcliffe – in pictures 2018 Nazanin Zaghari-Ratcliffe hugs her daughter Gabriella, in Iran after she was allowed to leave the Iranian prison, she is being held in, for three days. Zaghari-Ratcliffe was arrested during a holiday with her toddler daughter in April 2016. Iranian authorities accuse her of plotting against the government. Her family denies this, saying says she was in Iran to visit family. Free Nazanin Campaign/AP Nazanin Zaghari-Ratcliffe – in pictures Nazanin Zaghari-Ratcliffe with her husband Richard Ratcliffe and their daughter Gabriella. Nazanin is serving a five-year prison sentence for allegedly plotting to overthrow Iran's government. PA Nazanin Zaghari-Ratcliffe – in pictures June 2016 Richard Ratcliffe's daughter Gabriella had her British passport confiscated and was stranded in Iran with her grandparents after her mother Nazanin was jailed. He left left a giant birthday card on the doorstep of the Iranian embassy in central London to mark her second birthday in June 2016. PA Nazanin Zaghari-Ratcliffe – in pictures Nazanin has spent some of her prison sentence in solitary confinement. PA Nazanin Zaghari-Ratcliffe – in pictures Nazanin Zaghari-Ratcliffe with her husband Richard and daughter Gabriella. Family Handout Nazanin Zaghari-Ratcliffe – in pictures July 2016 Richard Ratcliffe delivering a letter of petition with his mother Barbara Ratcliffe and MP Tulip Siddiq, to 10, Downing Street on the 100th day of her detention, on July 12, 2016. Getty Nazanin Zaghari-Ratcliffe – in pictures Supporters of Nazanin Zaghari-Ratcliffe held a vigil outside the Foreign and Commonwealth Office to mark her 707 days in captivity. Getty Nazanin Zaghari-Ratcliffe – in pictures January 2017 Richard Ratcliffe holds a '#Free Nazanin' sign and candle during a vigil for for wife on January 16, 2017. The vigil, being held outside the Iranian Embassy in London marks one year since the Washington Post journalist Jason Rezaian and other US-Iranian dual-nationals were released from prison in Iran. Getty Nazanin Zaghari-Ratcliffe – in pictures Nazanin with her daughter Gabriella before they were detained by Iranian authorities. Change.org Nazanin Zaghari-Ratcliffe – in pictures September 2017 Gabriella, who is three-years-old in this picture, has now spent two years away from her mother. Richard Ratcliffe Nazanin Zaghari-Ratcliffe – in pictures November 2017 Foreign Secretary Boris Johnson meets with Richard Ratcliffe over Nazanin's case. They meet just days after Johnson told a parliamentary committee that she was in Iran "training journalists". WPA Pool/Getty Nazanin Zaghari-Ratcliffe – in pictures November 2017 Actor Emma Thompson braved pneumonia to support Richard Ratcliffe in leading demonstrators before a march in support of Nazanin in November. Reuters Nazanin Zaghari-Ratcliffe – in pictures November 2017 Richard Ratcliffe after the march said: 'It is profoundly moving to see so many people here.' REUTERS Nazanin Zaghari-Ratcliffe – in pictures November 2017 A picture of Nazanin Zaghari-Ratcliffe shown on Iranian state TV as part of a report that made fresh allegations against her. They said she had been recruiting for banned broadcast services, as well as 'opposition cyber teams'. Nazanin Zaghari-Ratcliffe – in pictures December 2017 Iranian president Hassan Rouhani greets British Foreign Secretary Boris Johnson at the presidential office in Tehran, Iran. Johnson visited Tehran to discuss the fate of detained Nazanin Zaghari-Ratcliffe. EPA Nazanin Zaghari-Ratcliffe – in pictures Nazanin Zaghari-Ratcliffe with her daughter Gabriella. PA Nazanin Zaghari-Ratcliffe – in pictures December 2017 Photos of Richard Ratcliffe and his wife Nazanin Zaghari-Ratcliffe on display at their home in north London. Mr Ratcliffe said he believed there was "still a chance" she may be released from an Iranian prison in time for a dream Christmas together. Unfortunately that didn't happen. PA Nazanin Zaghari-Ratcliffe – in pictures February 2018 Richard Ratcliffe delivers a petition and a letter addressed to the Iranian Deputy Foreign Minister Abbas Araghchi to demand her release, at the Iranian Embassy in London on February 21, 2018. He also left support letters for his spouse in the country's embassy, amid a visit by a deputy foreign minister. AFP/Getty Nazanin Zaghari-Ratcliffe – in pictures August 2018 Foreign Secretary, Jeremy Hunt meeting Richard Ratcliffe. Hunt has pledged to do everything possible to secure the release of a charity worker jailed in Iran Jeremy Hunt/PA Nazanin Zaghari-Ratcliffe – in pictures August 2018 Nazanin Zaghari-Ratcliffe hugs her daughter Gabriella, in Iran after she was allowed to leave the Iranian prison, she is being held in, for three days. Zaghari-Ratcliffe was arrested during a holiday with her toddler daughter in April 2016. Iranian authorities accuse her of plotting against the government. Her family denies this, saying says she was in Iran to visit family. PA

A letter from the pair, according to CHRI, read: “We are striking not only to demand our immediate freedom, but to ask for justice for the countless, thousands, unnamed yet not forgotten men and women who have suffered the same fate as ours or worse, and have been imprisoned in Iran, having committed no crime.

“This Christmas Eve, we ask you to join us for one day in foregoing food and water to express solidarity with us, while we will continue our strike beyond Christmas.

“We hope we will be celebrating with you in more than spirit this time next year.

“Thank you for your support. It means the world to us and gives us the strength to keep fighting.”

In June, Ms Moore-Gilbert pleaded with Scott Morrison, the Australian prime minister, for help to secure her release.

According to CHRI, she wrote: “The Revolutionary Guard have imprisoned me in these terrible conditions for over nine months in order to extort me both personally and my government.

“They have also attempted to use me as a hostage in a diabolical plot to lure my husband, an Australian permanent resident (and soon to be now citizen) into joining me in an Iranian prison.

“There is no hope for a fair trial. Indeed a guilty verdict has been predetermined in a legal system wholly controlled by the Revolutionary Guards. I came to Iran as an academic researcher and consider myself a political prisoner.”

Trials in Iran’s secretive legal system are often criticised for lack of evidence and not meeting basic standards of due process.