A science teacher shouted "die, die, die" as he beat one of his pupils around the head with a dumbbell, a court heard today.
Peter Harvey, 50, attacked the 14-year-old boy, who cannot be named for legal reasons, with the 3kg weight after he confronted the child for misbehaving in class, Nottingham Crown Court heard.
The moments before the attack at All Saints' Roman Catholic School in Mansfield on July 8 last year were filmed by a pupil.
Students could be heard calling Harvey a "psycho" after he tried to restore discipline during his science lesson.
Stuart Rafferty QC, prosecuting, told the jury that in December 2008 Harvey was sent home from the school after telling its education advisor he might harm somebody.
He stayed off work until April 2009 when he returned to the classroom.
Mr Rafferty said Harvey was "well, happy and in a positive frame of mind" on the morning of the attack.
He said: "A girl who had behaviour difficulties was being disruptive and was messing about with a white board and then started messing about with a window blind.
"He told her to stop and there were words between them. He seems to have pulled her away from the window by her bag on her shoulder and shouted at her and it was alleged he kicked her.
"She left the classroom in a state of tears and some of the class took exception to the way she had been treated and started calling him a psycho.
"He didn't seem to respond to that and told the class to get on with their work.
"The boy began to mess about with a wooden metre rule. He was wandering about the classroom with it, sword fighting with another pupil, that sort of high jinx."
Mr Rafferty added: "He told him to put it down and he did. The boy then took out a metal bunsen burner stand and was waving it about in a similar way.
"Mr Harvey chased him around the classroom and it came to a point when the boy told him to 'f*** off'.
"That seems to have lit the blue touch paper because Mr Harvey grabbed him by his collar and started dragging him out of the classroom.
"He did not meet with much resistance from the boy.
"He got him out of the classroom and down the corridor into a preparation room.
"He threw him to the ground and armed himself with a 3kg dumbbell and began to hit the boy about the head with it.
"He struck at least two blows to the head which caused serious injury, really serious injury.
"At the time the blows were being struck Mr Harvey was only heard to say one thing.
"What he was saying was 'die, die, die'."
The court heard that one pupil tried to drag Harvey off the boy, who was lying on his back looking "frightened and confused".
The teacher was kneeling above him, raising the dumbbell to shoulder height for each of the blows.
The schoolboy was left with a fractured right temple bone and severe cuts to his head.
Mr Rafferty said: "No-one can say for one moment what happened to this boy was deserved or justified.
"What he (Harvey) did was grossly disproportionate to the wrong inflicted on him by the boy or other members of the class.
"There was simply no excuse for what happened.
"To his credit Mr Harvey has never sought to portray himself as some sort of hero."
The court heard that Harvey later told police he felt like he was watching himself on television.
He said he was not feeling any emotion and "couldn't think at all".
The jury was told Harvey has admitted one count of grievous bodily harm without intent.
He denies a charge of attempted murder and an alternative charge of grievous bodily harm with intent to cause serious injury.
The prosecution alleges he knew what he was doing when he attacked the pupil and it was not a moment when the "red mist" descended and he was unaware of his actions.
One 15-year-old girl who was in the Year 9 class said she confronted Harvey about his behaviour moments before the attack.
She said: "I said to him, 'Sir, I think you are having a mental breakdown' because people were scared of him. He started murmuring something about killing me."
The girl told police in a videoed interview shown to the jury today how the teacher, who appeared in the dock dressed in a beige suit and brown tie, lost his temper with his victim.
She said: "He grabbed him by the neck and forced him out into the corridor.
"The class ran out and he got him to the floor.
"By this time he was doing something to him.
"He grabbed a weight and hit him on the head constantly.
"He didn't stop and blood was everywhere. Everyone was screaming and then two people went and got teachers.
"I ran off. Everyone was screaming about what happened."