A former student of Marylands School in Christchurch has described it as a meat market with a rampant sexual culture.
The school, which was run by the Catholic Order of St John of God between 1955 and 1984, is under investigation by the Abuse in Care inquiry.
James Tasker, 53, was sent to the special school at the age of 14.
He said what the Brothers who ran the school did to the boys was disgusting.
''It was just open slather at school. It was like going into the butchers shop and choosing which meat you would like to eat tonight. It is absolutely disgusting. The Catholic Church has a lot to answer for. It is absolutely shocking what they did.'
''They had full run of the house and could do what they liked, when they liked.''
He said lucky for him he was big for his age, and was able to fight off most sexual attacks.
Tasker said he witnessed the Brothers sexually abusing students every day, and older boys abusing others as young as five years old.
''Right from the beginning of my time at Marylands I was aware there was a huge amount of sexual behaviour happening between the Brothers and the boys and also between the older and younger boys.
''The abuse was shocking, it was on a day-to-day basis.
"I used to sit there at night listening to the boys moaning and groaning because the Brothers were playing with them,'' he said.
On one occasion when a Brother tried to abuse him in the shower block for a second time, he became enraged and fought the man off.
''I just about ripped his head off. I put 39 stitches in his head. I took out two hand basins with his head. I just about killed the prick.''
He said he told the St John of God Brothers to call the police.
''I said it will shut the school down in seconds.''
But police were not called.
''I should have been laid with charges for what I did to this Brother. I absolutely wrecked him.
''They didn't call the police because they didn't want to open a hornets' nest.''
Tasker told his mother about what was going on at Marylands.
''She also knew I could handle myself. She did put in a complaint, but it was obviously just brushed under the carpet. They did nothing.''
He told the inquiry he had not engaged with the Catholic Church at any stage about the abuse he suffered.
''The Catholics are the bloody worst. They put these pricks into schools and they put a white collar around their necks and they think they are God.''