The British-Egyptian maths professor Laila Soueif is being treated at St Thomas’s Hospital.
She is the mother of Alaa Abdel Fattah, who is Egypt’s most prominent political prisoner.
He a prominent role in pro-democracy protests in Egypt in 2011 and has been in prison almost continuously since 2014.
Laila Soueif went on hunger strike in September 2024 when her son’s sentence should have ended.
She’s calling on Prime Minister Sir Keir Starmer and his government to find a way to get Egypt to release him.
The Foreign Office says it is committed to securing Alaa Abdel Fattah’s release.