Hashem Abedi - brother of Manchester Arena bomber Salman - and the Parsons Green failed Tube bomber Ahmed Hassan have been jointly charged with assaulting a prison officer at HMP Belmarsh.
The two convicted terrorists have been charged with actual bodily harm.
A third man - Muhammed Saeed - has been charged with the same offence and Abedi has also been charged with a second charge of assaulting an emergency worker. According to the BBC Muhammed Saeed, 22, from Manchester, admitted possessing terrorist documents at the Crown Court in Kingston in June 2020. He awaits sentencing
This was a second prison officer, Scotland Yard said.
Abedi is just five months into a 55-year sentence for his involvement in the 2017 terror attack in which 22 people died.
Abedi, Hassan and Saeed will appear in court on April 7.