Noticing an obstruction in the school corridor, a teacher attempts to bring a group of children to a halt. One lad fails to notice the teacher and barges into him. An argument ensues, tempers flare and the boy tells the teacher to **** off, before running away.
"This actually happened in a school in England and the case made the newspapers," Geoff Moss, a consultant on assertive discipline, tells the assembled teachers at Mintlaw Academy in Aberdeenshire. "The question is, what should he do next?
"Well, this teacher gave chase and there are two versions of what followed. The teacher says he and the boy slipped on the polished floor and they landed together in a heap. The boy's friends claim the teacher launched himself through the air at him with a flying rugby tackle."
This is a good example, Mr Moss says, of why being a teacher is difficult. In the heat of the moment instincts, honed by millions of years of evolution, can take over, which are worse than useless in a school. Long ago the ideal teacher - an intelligent but relaxed, affable character - went extinct because he or she did not have the wary, suspicious nature needed to survive on the savannah. So now all teachers are saddled with emotional responses that are essential when surrounded by predators, but a liability when surrounded by children.
"If you want to manage children's behaviour, you have to learn to manage your own," he says. But this is only the first step in creating an orderly classroom environment in which "teachers can teach and children can learn".
The most fundamental change is gettng away from the idea that children should and will behave themselves if they are simply told to do so. "Telling works when a child has all the necessary skills in place. But nowadays a lot of children don't. So all of us - no matter what our specialist subject - have to become teachers of appropriate behaviour."
Schools needed to replace the idea of behaviour management with that of behaviour education. This takes a shift in thinking rather than a set of new skills, because good behaviour can and should be taught using similar techniques to those teachers already employ with classes.
"Imagine teaching maths in the same way as we teach, or rather don't teach, behaviour," Mr Moss continues. "We would give the class a set of maths problems without any explanation of how to solve them. Then, once they have started, we'd ignore those who were solving the problems, giving them no feedback as to whether they were succeeding or failing. But we would warn those who were getting them wrong that if they didn't improve they would be in serious trouble. Then, if they did not respond to the threat, we'd throw them out of the class.
"It sounds the complete opposite of teaching, doesn't it? But that's what we do with behaviour.
"The habit of giving priority to those who misbehave, who do not follow directions, is a hard one to break. It will take time to change your own pattern of reacting and you have to work at it before it can become automatic.
"Count the number of negative and positive comments during a lesson and try to increase the number of times you provide supportive feedback. The change in behaviour comes first from the teacher, then from the children."