The attacks happened in the playground of the school
A teacher has spoken of his anger after he and a colleague were attacked by a 14-year-old schoolboy.
The teenager - who cannot be identified because of his age - punched one male teacher and knocked the man's female colleague unconscious in the playground of the school in Cardiff.
The boy was sentenced on Tuesday to four months detention and training after the attack on two teachers at the school.
He was described in court as a "serious danger to the public" after admitting actual bodily harm, assault and harassment.
Speaking to BBC Radio Wales on Wednesday, one of the teachers said he was still angry about the incident, but he was glad the teenager had been punished by the courts.
"To be quite honest, I do still feel anger, and I do feel bitterness towards the boy for the injuries he caused to my colleague," he said.
"I feel he was exploiting the system. Such behaviour tends to be targeted at teachers as some juveniles do recognise that the system protects them quite well."
The court had heard that he had been permanently excluded from the school and had returned to see his friends.
The teacher told Radio Wales' Good Morning Wales that he had just finished teaching a lesson when he heard a disturbance involving two boys outside the classroom.
He recognised one as a pupil who had been permanently excluded six months earlier, and asked him to leave.
The boy grabbed the man's name tag and screwed it up. The teacher decided to follow him out of the school building in case there were problems, and was assaulted.
"He punched me across the jaw and he punched a female member of staff, who fell to the ground," he said.
His colleague was knocked unconscious, and was so traumatised she has has had to undergo counselling since the incident.
Despite the assault, the teacher said he had not been put off teaching, but he admitted: "It has made me appreciate some of the dangers of the profession, and how teachers can be quite vulnerable."
He said he was glad the teenager had been given a spell of detention, but he added: "Whether the sentence is strong enough to be a deterrent for him in the future, or for other juveniles in his position, I don't know."
During the juvenile court hearing, it was heard that the boy had been in trouble at school several times before the day of the attacks.
Alex Dubljvic, prosecuting, said: "He was a major problem causing major disruption at the school.
"He was abusive to staff, was involved in fights with other pupils, was caught smoking, did not go to lessons and was making hoax calls."
Such was his reputation, the court was told, that on spotting the boy in school grounds, female members of staff were "so frightened that they locked the doors of classrooms".
During the subsequent altercation, the teenager punched a male teacher and knocked a woman teacher unconscious with a single blow.
The female teacher told police the boy had clenched his fists "like a boxer".
She said: "He had an evil look on his face and was ranting.
"I turned away to get help then felt a big thud to the side of my face.
"I felt my brain rattling around inside my head. The next thing I remember is lying on the floor."
The court heard how the teacher, who had been taken to hospital with a suspected broken jaw, had recovered but suffered flashbacks three months after the attack.
Sentencing the boy, youth court chairman Lenna Pritchard-Jones said: "We feel the offences are very serious because of the nature and extent of the harassment and violence towards the victims.
"You are a persistent offender and a serious danger to the public."
His solicitor, Geraint Richards, said the boy was "well-balanced and well-mannered" until the death of his grandmother three years before when he began distancing himself from the rest of his family.
The boy's parents were law-abiding people who were mystified by his behaviour, Mr Richards said. On one occasion, the boy's own father had reported him to the police.
He said the family was planning to make a fresh start and move out of the Cardiff area.