The worst thing that ever happened to Martin* in the classroom was when he was sexually assaulted by a pupil. He was standing in front of a Year 10 history class when one of the boys left his seat and came towards him. “He walked up to me and started massaging my breasts,” Martin says. “I stared in complete disbelief and he came back and did it again.”

This was the closest Martin, a humanities teacher, has come to being pushed over the edge by his pupils. “I nearly lost it when this happened,” he says. “I only held back because I couldn’t believe what had happened. I was white with anger.”

Assaults by pupils are an occupational hazard for many teachers. A survey by the Teacher Support Network published in June found that two in five teachers had been physically assaulted by a pupil, and almost half of respondents had been threatened with violence.

Nor is it only physical. The survey found that 95 per cent of teachers suffer swearing or backchat. For two-thirds, this is a weekly occurrence. For one in five, it happens every day.

This may help explain the reaction of some teachers to events at a school in Nottinghamshire last month. Peter Harvey, a science teacher at All Saints’ Roman Catholic School in Mansfield, has been charged with attempting to murder a pupil in a classroom incident less than a fortnight before the end of the school year. Jack Waterhouse, 14, suffered a fractured skull and spent six days in hospital after the alleged attack. The case has been adjourned until the week beginning September 28.

While details of what happened will not be revealed until the case comes to court, reports that it involved issues of pupil behaviour have prompted a more ambivalent response than you would expect for a straightforward assault. A group calling itself Justice amp; Support for Peter Harvey on the social networking site Facebook had 1,843 members at the time of going to press. Hundreds of blog posts record sympathy for Mr Harvey, including several threads on The TES website.

“The reaction of every serving teacher to whom I’ve spoken is exactly the same: `There but for the grace of God goes every single one of us’,” says Jon Berry, senior lecturer in education at Hertfordshire University.

Despite being the victim of assault, Martin’s view is that it is not the one-off outbursts that represent the worst in pupil behaviour. Instead, it is the drip-drip of minor disturbance, with no incident enough in itself to justify invoking disciplinary procedures, but with a cumulative effect that is highly disruptive.

Talking through the lesson, coming in late, arriving unprepared and having to borrow pen and paper, asking to go to the toilet, asking “stupid” questions - all of these combine to frustrate attempts to teach.

“The biggest problem is death by a thousand cuts,” Martin says. “There are always one or two kids at the centre and if the other kids see that is where the power lies, that is where they’re going to go. The hardest thing is when you look at the good kids and they’re looking at you, and you can see they’re thinking: `Is there nothing you can do?’ But there is nothing you can do.”

His experience is that teachers receive little or no support from senior managers when they try to discipline problem children. The Year 10 pupil who assaulted him was forced to apologise and sent to an isolation unit in the school for three days, but then returned to class and told if his behaviour was good for three weeks he would be rewarded with a Mars bar.

Martin describes himself as a “big guy”. He has taught in tough schools in New York and is a former US Marine. But he believes the standard of behaviour is worse in the UK. “I’ve taught in Brooklyn, but the first time I was told to fuck off by a pupil was in Cornwall. Respect seems to be a one-way street,” he says.

He believes a shift in power - from teachers to pupils - has exacerbated the problem in recent years. “Kids have this sense of being bullet-proof,” he says. “They know if they’re sent out of the class, all they have to do is apologise. And if the school gets tough, their mum or dad will complain that their child is being bullied by the teacher.”

There is little consensus on the extent of poor behaviour in schools. According to Ofsted, only around 6 per cent of schools have a behaviour problem, but Terry Haydn, an academic who has carried out his own research into pupil behaviour, believes this is an underestimate. He suggests that behaviour during Ofsted visits may be unrepresentative of the pattern during the rest of the school year, and that the true picture is less reassuring.

As a result of interviews with teachers and heads in 80 different schools, Dr Haydn, a lecturer in education at the University of East Anglia, believes pupil behaviour is a problem in nearly all schools.

The most common scenario, he says, is that schools have a mixture of classes: some can be managed comfortably, others require careful handling. Dr Haydn has developed a 10-point scale of classroom behaviour (see panel), and says few schools consistently remain at levels nine or 10, where the teacher is firmly in control. When levels fall below nine, he says, children’s learning is adversely affected.

“In many schools, there are classrooms where some pupils limit the learning of others and the teacher is not in complete control,” he says.

A survey carried out by the NUT last year confirms that low-level disruption is a major threat to classroom management. Problems that occur on a daily or weekly basis include: refusing to work (58 per cent); inappropriate interruptions (79 per cent); offensive language (60 per cent); answering back (73 per cent) and abusive or insulting personal comments (30 per cent).

Christine Blower, NUT general secretary, says the picture is not one of schools erupting in anarchy, but of persistent problems in a minority of schools. “In the vast majority of cases, schools are orderly and safe places,” she says. “There are a very small number of schools where there are a small number of pupils whose behaviour is getting worse.”

Jules Donaldson, a secondary teacher from Sandwell in the West Midlands, says that while most teachers know how to cope with a one-off aggressive outburst, it is harder to deal with disruption that means children are not doing what they are meant to be doing at the time they are meant to be doing it.

“It can be very difficult to pinpoint and say `This is what happened’, but it is a continual pushing of the boundaries,” says Mr Donaldson, who called for action on behaviour at this year’s annual conference of the NASUWT teachers’ union. Left unchecked, low-level disruption can easily flare up into something much worse. “It is a drip-drip frustration that can lead to confrontation,” he says.

He believes sanctions are available to schools but school managers are often reluctant to use them in case this is viewed as a failure. Exclusions can mean a loss of funding, while internal punishments, such as “sin-binning” children, can be onerous for teachers because separate work needs to be set.

It was the steady drip-drip of poor behaviour that pushed Francis Gilbert over the edge. He had endured pupils throwing things at him, barricading his classroom and fighting with each other, but the day he grabbed a Year 7 boy by the arm and threw him out of the room, it was over a relatively trivial incident.

“He refused to do any work and persistently disrupted my lesson,” Mr Gilbert says. “What he had done was quite minor, but I was at the end of my tether, constantly dealing with his misbehaviour.”

Although the boy complained about being manhandled, he was persuaded by the deputy head not to take it further.

But Mr Gilbert recounts daily battles to try to get his pupils to learn. One class was studying Arthur Miller’s A View from the Bridge and after Mr Gilbert explained how Eddie was attracted to Catherine, his niece, the class started to chant “Eddie wants to fuck Catherine”, followed by throwing things, shouting and pushing the furniture against the door.

Mr Gilbert, who has chronicled his experiences of teaching in east London in the best-selling book I’m a Teacher, Get Me Out of Here, says when he raised the issue with senior managers he received neither support nor sympathy.

“They said it was my problem I couldn’t control the class and that I should improve my lessons, but no one came in to help - they told me to get on with it,” says Mr Gilbert, who now combines supply teaching with writing.

An assumption that the teacher must be at fault is a common reaction to reports of classroom misbehaviour. But Dr Haydn believes even good, experienced teachers will have problems controlling some classes. He argues that attempts to provide solutions to classroom management problems reinforce the impression that teachers are at fault, and that if only they used the correct techniques then order would be restored.

The reality, he suggests, is rather different. Some children just don’t want to learn, some schools have a disproportionate number of these children, and there is very little individual teachers can do about it.

Dr Haydn of the University of East Anglia rejects the idea that there is a “magic bullet” solution, and says instead the response should be to accept that a number of different factors are involved.

“We have to get everybody on board to support schools and we need better arrangements for internal exclusion, so kids aren’t allowed to spoil the learning of others,” he says.

Ralph Surman, a deputy head in Nottingham and a member of teaching union ATL’s national executive, believes the trend towards inclusion and the decline in teacher autonomy have worsened the problem in recent years.

Inclusion means children with behaviour problems who would previously have been in special schools are remaining in mainstream schools, while increasing pressure from Ofsted and league tables mean teachers have less time to devote to behaviour management.

“The key to managing behaviour is taking time to build relationships,” Mr Surman says. “When your priority is raising sub-levels of achievement, you don’t have time to do that.”

He argues that the pressure on teachers to set a high level of challenge in every lesson can be too much for some children.

“I’m not at all surprised that a certain element will just switch off,” he says. “Teachers are being scrutinised on the performance of every single child in microscopic detail and that has a detrimental effect on a process that we’re making far more complicated than it needs to be.”

Alison Ryman, ATL policy adviser, says that while the ATL backs the principle of inclusion, the level of support to make it happen effectively in schools is not yet there. As a result, there has been a negative impact on classroom behaviour.

Mrs Blower of the NUT believes one of the key issues in helping teachers manage poor behaviour is reducing their workload. She says the pressures associated with teaching mean teachers do not always respond to classroom misbehaviour as they otherwise would. Workload pressure is made worse by large classes, a high-stakes school inspection system and league tables, she says.

“When teachers find themselves having to do a lot of things they don’t see as contributing positively to their teaching, they find themselves more under stress and less able to root out difficult behaviour,” she says. “That doesn’t mean every teacher is on the verge of cracking up, but it is an issue.”

She says most schools have policies in place to deal with poor behaviour, but there is scope for teachers to learn more about classroom management during their initial training.

“You obviously get better at it as you do more of it, but it’s harder if you’re starting from a lower level,” she says.

But Mr Berry says that while there may be only two or three sessions dedicated to classroom management during year-long teacher training, it is an ever-present undercurrent.

“Behaviour management is bound up with lesson planning,” he says. He believes there should be more emphasis on understanding why children behave as they do and preventing poor behaviour before it happens, rather than dealing with it once it has occurred.

For Clare, it was her school’s failure to deal with poor behaviour that led to her taking almost two months off with stress last term. In her case, it was one particular boy who caused problems in her Year 5 class at a south London primary school.

She says the boy had been aggressive all year, attacking both her and other pupils - disruptive behaviour that culminated in an attempt to stab her with scissors. She says that the school attempted to take action, but the head was reluctant to use his ultimate sanction: exclusion.

“We were filling in behaviour improvement plans, ticking boxes and holding meetings, but he was still being sent back into class,” she says. “It was daily violent and aggressive behaviour and it was extremely upsetting for the rest of the class.

“Every lesson he would be screaming, running up and down and calling me a fucking bitch. I couldn’t teach because every time I opened my mouth, he would start.”

She says she became depressed and her self-esteem plunged. “I felt a failure, but he was punching me and spitting at me every day. There wasn’t a day in class when something didn’t happen.”

The Teacher Support Network survey published this summer found that 54 per cent of teachers did not believe their school’s behaviour policies were being effectively enforced. Julian Stanley, the network’s chief executive, says school leadership teams should ask themselves if they are providing enough information and support to staff.

He says if teachers recognise they have a discipline problem in their class, it is important that they step back and look for help in developing ways to tackle it. But he recognises that workload and other pressures can make this harder for teachers than for those in some other professions.

For some teachers, there comes a point where one pupil takes them to the edge. This child may be the chief culprit or may just happen to have said the wrong thing at the wrong time. For Clare, there was no doubt who would have been the object of her wrath: her 10-year-old tormentor.

“There were times when I got so angry with him,” she says. “I wouldn’t hit him, but I just wanted to get him out of the room. It is really difficult to hold yourself together in front of the class when somebody is constantly swearing at you.”

The line between being in control and losing it can be a fine one, but it is a line that some teachers walk every day, and that many walk at some time in their working week. The times a teacher steps over the line may make the news, but they are the one-offs, the exceptions. But the fact they are one-offs does not mean that everything is hunky-dory.

*Some of the names in this article have been changed.

Dr Haydn’s 10-point scale

• 10. Teacher completely relaxed and comfortable and able to work without concern.
• 9. Teacher in control, but has to exercise some authority at times to maintain working atmosphere.
• 8. Teacher can establish and maintain relaxed and co-operative atmosphere, but this requires considerable thought and effort.
• 7. Class bubbly and rowdy. The few pupils who mess around stop when asked to do so.
• 6. Major effort to establish and maintain a calm atmosphere. Several pupils will not remain on task without persistent exhortation.
• 5. The teacher feels awkward or embarrassed if a visitor, such as the head, a governor or inspector, comes in because their control of the class is limited.
• 4. Control is limited and it takes time to get the class to listen. Lesson preparation is about control rather than education.
• 3. Teacher dreads the thought of the lesson. Major disruption, with children who want to work having difficulty.
• 2. Pupils are in control. Teaching is ignored, with staff just hoping children will be in a good mood, leaving them alone to chat to each other.
• 1. The teacher’s entry into the classroom is greeted by jeers and abuse. Such staff have to turn a blind eye to bad behaviour to avoid confrontation. They often wish they had not gone into the profession.