Paul Edwards, 57, said he thought he would be killed when he was set upon by Hashem Abedi, Parsons Green Tube bomber Ahmed Hassan and Muhammed Saeed, who spoke about carrying out a knife attack in London.

Abedi, 24, conspired with his elder brother and suicide bomber Salman Abedi, who killed 22 people and injured hundreds more at the Manchester Arena on May 22, 2017.

Abedi is seen smiling in CCTV footage before he, Hassan and Saeed storm Mr Edwards' office, where he operated an "open door policy".

Mr Edwards, a custodian manager who has worked at Belmarsh for 25 years, told jurors he was hit with a chair, repeatedly punched and kicked on 11 May 2020.

"I feared for my life, and I genuinely thought if I hadn't fought back I would've ended up with at least extreme injuries or dead," he said.

He said "it felt like a lifetime" before colleagues, including Nick Barnett, who has been a prison officer for 21 years, came to his aid seconds later.

"It was just like a pack of animals on Mr Edwards," said Mr Barnett.

Mr Edwards, who can be seen with head injuries and blood on his shirt, suffered a laceration to his head, bruising to his back, rib cage and face and has lasting damage to his hearing.

"They had shown disrespect for society and its rules"

All three prisoners denied assault causing actual bodily harm to Mr Edwards, but were found guilty by a jury after about three and a half hours of deliberations.

Abedi was also found guilty of assault by beating of an emergency worker over the attack on Mr Barnett.

Before he was sentenced, Abedi told the judge Mrs Justice Cheema-Grubb: "I don't think the sentence is going to make any difference.

She sentenced him to another three years and 10 months consecutive to his current sentence. Hassan, who is serving a life sentence with a minimum term of 34 years, and Saeed, who is serving a five-year sentence, were both handed three-year jail terms.

The judge said they had "shown disrespect for society and its rules" with the prison officers facing "danger every single day".

In a closing speech, Abedi said: "I don't think we get treated like other prisoners."