Is it safe for me to go to town? Will he search me out? Noises at night - getting paranoid. Don’t want my family involved. Do I need this hassle?” These notes from John Skelton’s diary - charting his thoughts for a year following an assault - show the devastating effects on one teacher of being attacked by a parent.

John Skelton, 44 years old and a teacher for 23 years, is head of languages at a south Wales comprehensive. A cheerful-looking, heavy-set man in off-duty jeans and check shirt, he looks an unlikely victim of physical intimidation. A keen Cardiff City supporter, he played football and swam before the assault and considered himself fit and healthy.

But in May 1997, when an aggrieved father launched a violent attack on him at school, there was little Mr Skelton could do. “I keep eye contact to let him know that I can sense a fist or head-butt coming, hoping this will deter him. I feel totally at risk, unable to defend myself. Outside it is noisy. I know I won’t be heard, even if I manage to shout. He is still ranting, swearing, pulling me to and fro. I want to get my blow in first but know, with no witnesses, I daren’t risk it,” read the notes he made immediately after the incident.

The assault came out of the blue. As a year tutor, Mr Skelton had pastoral responsibility for 120 Year 8 pupils. One, 13-year-old “Robert”, had been temporarily excluded for repeated disruptive behaviour. His parents - whom Mr Skelton had never met - were invited into the school on the morning of the boy’s return to discuss his re-entry. But the day before Robert was due back, his father turned up unannounced.

Mr Skelton gave the man a friendly reception and ushered him into an interview room, alone, as was his habit. “He seemed right as rain,” says the teacher. The 29-year-old man - until then polite and reasonable - slammed the door behind them and started waving the exclusion letter in Mr Skelton’s face, shouting and swearing, before grabbing the teacher by the throat. He shook Mr Skelton repeatedly. “It went on for a couple of minutes,” says John Skelton. “I was trying to calm him down.” The teacher made a break for the door, with Robert’s father kicking him in the groin as he escaped into the crowded corridor. As Mr Skelton shouted for help, the head and another staff member came running.

John Skelton, a size 8 footprint on the front of his trousers, ripped shirt and a tie so tight it had to be cut off, was severely shocked. But his response was unambiguous. “Right away, I knew I wanted something done about it,” he says. “I was adamant I wanted to report him to the police.”

After the police had come to school and taken his statement, and one from the head, John Skelton’s wife, Lynne, a teacher at another inner-city comprehensive in Wales, came to collect him. First, he walked through school, ripped shirt and all, to get his briefcase. “I looked like medallion man. But I wanted the kids to see I was alive - because all sorts of stories circulate - and that I’d be back the next day.”

In fact he didn’t return for a month. Doctors at the casualty department said he had a whiplash injury. His oddly blotchy hands were typical of someone who’d had a car crash or other severe shock, they told him. The following day, Mr Skelton’s GP confirmed the whip-lash, told him he was still in shock and referred him for twice-weekly physiotherapy.

His union, the National Association of Schoolmasters Union of Women Teachers, was supportive. But, as the police appeared to drag their feet in pressing charges, Mr Skelton’s turmoil began. “Cold shivers at times - sleep disrupted - every minute detail over and over in my mind,” run the notes. “Still police have done very little. Why won’t they arrest him formally? Getting angry - mixed feelings all the time. My wife and kids suffering because of me.”

Despite a loss of mobility in his neck, John Skelton’s physical injuries started to improve fairly quickly. But his psychological state showed little improvement. As the weeks went by, Mr Skelton was unable to stop thinking about the incident. He woke regularly at 4am “with it all buzzing round in my mind”. The diary continues: “What happened? Why? Could I have reacted differently? Why didn’t I see what he was going to be like?” Robert’s father had been neatly dressed and polite until he was alone with his victim. But, as Mr Skelton points out, teachers cannot judge parents by their appearance or manner. “Most of our kids are streetwise, down-to-earth and a pleasure to deal with,” he says. “And it’s the same with the parents. They come in covered with tattoos, wearing a T-shirt in deepest winter, and say ‘Mr Skelton thank you for everything you’re doing’. If I refused to see those who looked dubious I’d see hardly anyone.”

John Skelton was deeply unsettled, he believes, by being set upon in school. If it had happened at a rugby match, he could have got over it quicker. “Why has it got to me? Circumstances, situation. I know it’s not safe to walk into the middle of rival fans at City, but in doing my job in my domain under my control, it’s like a break-in, a violation. Where is safe?” he wrote.

When the summer holidays came, instead of improving, John Skelton’s mental state got worse. He was irritable at home with his wife and two children, and distracted. By August, his doctor said he was suffering from mild depression and put him on anti-depressants. The drugs did not help. But Mr Skelton has managed to regain his equilibrium by striking back through the legal system.

Although he says he has had excellent support from the head and local education authority in pursuing the case, he was aware these things could not be taken for granted. The head was new in the job and the school trying to turn around a poor reputation. Many people’s interests might have been better served had the case, with the inevitable publicity, never come to court.

Even Mr Skelton - now applying for senior management posts - had to make a calculation about speaking out. Should he risk being seen as having poor interpersonal skills, unable to calm an overheated parent, or as someone with an injury, who might be liable to head for early retirement?

He decided to pursue justice on principle, and for the sake of other teachers. “I want to get out the simple message that assault on a teacher equals court case equals prison sentence,” he says. “Then maybe the public will see what we have to put up with, and see that we not only deserve protection, but get it.”

Last October, six months after the attack, the case finally came to court. Robert’s father pleaded guilty to assault and criminal damage. Three weeks later, he was sentenced to four months’ imprisonment. Robert himself left the school the same day, and is now attending another.

With justice done, John Skelton’s recovery is complete. Despite the fact that his assailant is now out of prison, he sleeps at night and no longer feels the need to look over his shoulder in the town centre, and his neck has loosened up. “It changed overnight once he was sentenced,” he says. “I didn’t gloat, I was just relieved. I want it known that you can’t get away with it. I’m sure there are a lot more assaults out there that nothing is done about.”

Teachers who have had similar experiences and would like to contact John Skelton can write to him co The TES, Admiral House, 66-68 East Smithfield, London E1 9XY