One of the men convicted of murdering soldier Lee Rigby has admitted assaulting a nurse at the high-security Broadmoor Hospital.
Michael Adebowale, 28, punched a healthcare assistant while being held in the secure hospital on July 20 last year, Reading Crown Court heard.
Adebowale was serving a 45-year term for the 2013 killing of Fusilier Rigby in Woolwich, south-east London.
He was jailed for eight months to run consecutively to his sentence.
Adebowale, who now uses the name Ismaail Kuti, along with Michael Adebolajo, drove into Fusilier Rigby with a car before hacking him to death.
The court heard Kuti had been a patient at Broadmoor when health assistant Jason Kaplin asked him to turn down music he was playing through his MP3 player on the TV in the day ward.
Prosecutor Sarah Whitehouse QC said Kuti had returned to his room “upset and annoyed” before reappearing and attacking Mr Kaplin, who was doing paperwork at his desk.
The nurse was taken to hospital for an injury to his left jaw which took six weeks to heal, the court heard.