Up to 150 pupils "rioted" through the corridors of a new academy in England last week as a pupil protest degenerated into mayhem.
One pupil has also been permanently excluded after he is alleged to have threatened a teacher with a small knife used during a science experiment.
Five students were permanently excluded and another 25 were given temporary exclusions.
Staff are also threatening to ballot for industrial action unless urgent changes are made to Oasis Academy Mayfield in Southampton.
The school, which only opened last month, is sponsored by Oasis, a Christian charity and major academy sponsor. It already runs nine schools and is involved in talks about opening a further three.
Ron Clooney, from the NASUWT teaching union, said: "The school is a disaster. Parents, pupils and staff are unhappy with the way it's being run."
The incident occurred after a protest by Year 11s was hijacked by a number of pupils who went on the rampage.
Ruth Johnson, the school's principal, said the incident was serious, but had been exaggerated. She said around 40 pupils were involved.