The jailed Manchester Arena attacker and Parson's Green Tube bomber have been charged with assaulting a prison guard.
The two terrorists allegedly committed the attack against a member of staff while serving life sentences at HMP Belmarsh in London.
Hashem Abedi, who was convicted in March 2020 of plotting the Manchester Arena terror attack which killed 22 people, and Ahmed Hassan, who detonated a bomb on London's transport network, have been charged with the attack, as has Muhammed Saeed, 22.
Abedi has also been charged with assaulting an emergency worker who worked at the prison.
The alleged attacks took place on May 11, 2020. The three men are due to appear at Bromley Magistrates’ Court in London on April 7.
Abedi, 23, is currently serving 24 life sentences in prison with a minimum of 55 years before being considered for parole for his part in the 2017 Manchester Arena bomb attack.
His older brother Salman Abedi detonated a suicide bomb at an Ariana Grande concert killing 22 people and injuring more than 1,000. Last month, it was revealed Hashem had confessed to his role in the attack.
In 2018, Iraqi teenager Ahmed Hassan, now 21, was convicted of the 2017 Parson's Green tube bombing, which injured 51 passengers. He was sentenced to life in prison with a minimum term of 34 years.
His bomb partially exploded on a London Underground train.
Hassan, who arrived in the UK as a child asylum seeker, claimed to immigration officials that he had been groomed by ISIS and "trained to kill" and had been referred to the government's deradicalisation programme prior to the attack.
Last year, UK Justice Secretary Robert Buckland launched an internal review of the custodial management of terrorist prisoners after the attempted murder of a prison officer by inmates wearing fake suicide vests.
Ian Acheson, a former prison governor who carried out a 2016 government review of extremism in jails, said in October 2020 that he feared a prison officer could be taken hostage and killed, and called for urgent action to protect prison staff.
