A senior teacher whose girlfriend was the object of sexual gestures from a special-needs pupil attacked and injured the teenager, a disciplinary panel has heard.
David Thomas, known to his colleagues as Kevin, was seen lying on top of the 15-year-old boy at a special school in Bridgend after shouting at him in a side room.
The boy, referred to as pupil A, was left with facial injuries and marks to his body after the incident, which took place in November 2006, a disciplinary hearing at the General Teaching Council for Wales (GTCW) heard.
Mr Thomas, a craft, design and technology teacher who taught at the school - Ysgol Bryn Castell - for 18 years, was suspended and then dismissed following an internal investigation, but was later cleared of assault at Bridgend Magistrates' Court.
However, he could be banned from returning to the classroom if found guilty of unacceptable professional conduct by a GTCW committee.
Mr Thomas is accused of reprimanding pupil A when it was not his responsibility to do so, and acting outside the school's behaviour policy. He denies both charges.
Presenting officer Gwenno Hughes told the hearing that a female member of staff, referred to as teacher C, alleged that pupil A had made obscene gestures towards her.
Mr Thomas, who was in a relationship with teacher C, sought out pupil A and found him in a quiet room where pupils with behavioural difficulties are taken to calm down.
Witnesses Gareth Lewis and Lee Tucker both saw Mr Thomas talking with pupil A in the quiet room, but left. They returned to the room after hearing Mr Thomas raise his voice.
Mr Lewis, head of PE at the school, said: "I saw pupil A lying on the floor on his back with Mr Thomas lying on top of him." Mr Lewis told the GTCW that Mr Thomas said: "Don't you dare ever raise your fists to me again."
Injuries to the pupil were recorded as a swollen eye and top lip, marks on his back, neck and chest and finger marks on his arms.
Mr Lewis admitted that the school's behaviour policy at the time was "confusing", but said staff would automatically turn to Mr Thomas, who had a responsibility for discipline.
Mr Thomas has yet to give evidence, but in a police interview read out at the hearing he said he wanted to speak to pupil A because he abused a female member of staff, not because she was his partner.
He claimed he grabbed pupil A's wrists because he thought he was going to be attacked.
"Pupil A went to stand up with his fists raised, I took hold of both his forearms but my leg buckled and we fell to the floor," he said.
DC Paul Hatton, who conducted the interview, said Mr Thomas admitted leaving marks on pupil A's arms, but could not account for the facial injuries.
The boy claimed Mr Thomas kicked his legs from under him and threw him on the floor.
But Mr Thomas said: "There's no way the incident went the way pupil A stated. They are children, we are adults. I wouldn't do that to a child."
Andrew Williams, a child care officer at the school, said Mr Thomas was a very good teacher who would "not lay a hand on a pupil".
He said pupil A was one of the worst behaved pupils he had seen at Bryn Castell, and that he could "go off like a bomb for no reason at all".
The hearing will resume in March.
A TALE OF TWO TRIALS
A primary school teacher was found guilty of using unnecessary force against a pupil, despite being cleared in relation to the incident at a criminal trial.
Ian Reynolds, a former teacher at Maesmarchog Primary in Neath, was banned from the classroom for 12 months by the General Teaching Council for Wales (GTCW).
Mr Reynolds had previously been cleared of grievous bodily harm following a crown court trial. But the GTCW said he had used unnecessary force and also found him guilty of two other charges, including using the injured pupil's name to access pornography on a school laptop.
The GTC follows civil court rules: the standard of proof required is "on the balance of probabilities" rather than "beyond reasonable doubt".