Thirteen prison officers required hospital treatment after being attacked by teenage offenders during a weekend of violence at a youth jail.

Nineteen staff in total at Feltham Young Offenders Institution (YOI) in west London were injured as about a dozen young criminals, aged 15 to 17, mounted “unprovoked” attacks on officers.

They suffered fractures, broken noses, cuts, bruises and bites during the violence which started last Friday and continued through the weekend.

“They don’t need an excuse, they decided they were going to attack staff members, unprovoked. It was just wanton violence, simple as that,” said Mark Fairhurst, chairman of the Prison Officers’ Association.

“Feltham has a difficult cohort to deal with as these are the violent kids who are committing the knife crime in London. They don’t stop violence just because they are in a young offenders’ institution.

“They came up to staff, punched them in the face. When they got restrained, they bit staff. There’s some quite deep bites. It’s just unprovoked violence.”

Mr Fairhurst sparked a backlash on Twitter after tweeting that they should "Replace the term 'children' with 'violent young criminal' and you more accurately describe what @POAUnion members in the juvenile estate face.”

However, he was unapologetic over his comments and demanded that the attackers should be prosecuted and segregated, so they could be treated by psychologists to try to understand the motivation for their violence. "We will support staff and push for prosecutions,” he said.