Professor Raj Persaud is a consultant psychiatrist at the Maudsley hospital and senior lecturer at the Institute of Psychiatry in London "There is a key difference between people who become violent because of a trigger, such as a significant life event, and those who have always been violent. If a child becomes violent, the school needs to find out why, otherwise there will be no progress.
"Children who have always been violent often come from disturbed families that need outside help. In those cases, the school could write to the GP, with the family's consent, to request a child psychologist or family therapist. Generally, children who are violent have no self-esteem and a classroom can be a constant reminder that they are not doing well educationally; they use violence to reassert dominance, to make people afraid of them.
"Teachers must ensure that such children are physically isolated. If a school does not contain violence rapidly then other children will use it.
They will notice the power that it brings, that teachers are scared, and they will copy it.
"Teachers have to spot the warning signs. They need to know whether a pupil is being violent because they are emotionally aroused or are taking cold decisions to commit violence: that is, they are psychopathic. That is harder to deal with and will probably require psychiatric intervention.
"Teachers dealing with violent pupils need a great deal of support. They should be properly debriefed and advised at all times."