Teachers were most likely to act if children behaved against stereotype - when girls were involved in physical abuse or boys called girls names or ostracised them.

“There seems to be a consensus that boys ought to be able to cope with social bullying from girls, but other studies show that this is precisely the kind of bullying which is most damaging to the victim,” said Dr Mike Eslea, psychology lecturer at the University of Central Lancashire who convened a workshop on bullying at the conference. He based findings on responses to a questionnaire sent to 76 teachers in four primary schools.

He said: “Teachers seem to expect children to behave in gender-appropriate ways and dislike it when children step outside the stereotype. Teachers are generally perceiving indirect bullying as less severe, and this has a bearing on schools’ attempts to reduce bullying.”

As part of a Department of Health-funded three-year study into British families conducted by the Thomas Coram Research Unit, at the London Institute of Education, Dr Gavin Nobes, a psychology lecturer at the University of East London interviewed 220 families with seven and 11-year-olds, with some of the questions relating to bullying.

He found bullies tended to be smacked and hit more frequently than other children. It was also discovered that both bullies and their victims tended to have poor relationships with their parents and also that parents who are aggressive to others outside the family tended to have both bullying and bullied children. He concluded that harsh discipline and parents’ aggressive behaviour probably led to children being aggressive with their peers.