British-Egyptian pro-democracy activist Alaa Abd El-Fattah has “deteriorated severely” over the past two weeks in jail, his sister has warned.

Mona Seif said that some of their relatives have visited the writer, who had recently been on hunger strike at Wadi El Natrun prison in Cairo, and found the changes in his physical health to be “unsettling”.

Mr Abd El-Fattah has spent most of the past decade in jail and is currently serving a five-year sentence on charges of disseminating false news for retweeting a report in 2019 that another prisoner died in custody.

Since April he has either refused food entirely or been on a partial hunger strike, taking just 100 calories a day, and even spent a week without water, according to the campaign for his release.

He had intensified a hunger strike and halted all calories and water at the start of the Cop27 summit in Egypt to draw attention to his case.

It is believed that authorities began a medical intervention on November 10, prompting suggestions he was being force-fed, and his family received a note in what they believe is his handwriting saying: “I’ve broken my strike”.

Writing on Twitter one week later, Ms Seif gave an update on her brother’s health.

She said: “News from the visit are unsettling, @alaa deteriorated severely in the past 2 weeks, but at least they got to see him, and he needed to see the family so much.

“The family will share the full details later today, please bear with us.”

Earlier on Thursday, Ms Seif shared a photograph of their mother, Laila Soueif, in the waiting area of the Egyptian prison ahead of seeing her son for the first time in more than three weeks.

Alongside the photo, Ms Seif said: “The past two weeks seemed like a lifetime on their own: water strike, no communication or info, needing a proof of life.

“I am glad she will finally see him.”

In a letter to Ms Seif on November 5 – the day before Cop27 commenced – Prime Minister Rishi Sunak described the conference as an “opportunity to raise your brother’s case with the Egyptian leadership”.

He added that Middle East minister Lord Ahmad would update the family on the progress of negotiations after the UN summit which finishes on Friday.

The Foreign, Commonwealth and Development Office (FCDO) did not directly respond to questions about whether the family would receive an update from them on Mr Abd El-Fattah’s case by the end of this week.

An FCDO spokesperson said: “The Prime Minister raised Mr Alaa Abd El-Fattah’s case with Egyptian President Sisi on November 7 and made clear his expectation that the case is resolved swiftly.

“Our priority is Mr El-Fattah’s welfare and securing his immediate release.”