Children as young as 5 are consistently swearing at teachers, with nearly 20 per cent of primary school teachers claiming to have been subject to sexually abusive insults from pupils.

In a study commissioned by the National Union of Teachers, England’s largest teaching union, researchers also found that 75 per cent of secondary school teachers said that pupils used language such as “F*** you” or “I’ve f***** your mum” to one another.

And, according to the teachers, parents, far from helping to stamp out sexist language and bullying, are refusing to set children a good example.

Most experienced teachers said that sexist language had worsened in recent years, and they wanted schools to take action on the serious incidents of sexist bullying.

Language was as bad at primaries as at secondaries, teachers reported, and worst in failing schools. Lesbian and young women teachers were regarded as most vulnerable.

However, while all teachers are protected from sexual harrassment in the workplace under the Sex Discrimination Act, schools do not see it as a high priority, the report found.

At the same time, only around half of the serious incidents were reported to senior colleagues.

The NUT and the University of Warwick, which questioned 190 teachers in primary and secondary schools for the survey, said that some children used sexual swearwords in foreign languages.

Steve Sinnott, the union’s general secretary, said that the Government must insist that schools develop tough policies in order to discourage parents and pupils from using abusive language. “Sexist jokes, put-downs and harassment in schools all help create an atmosphere in which female pupils and teachers feel degraded,” he said. “Such behaviour is completely unacceptable.

“But schools cannot close society out at the gates — its influence will inevitably be seen in our schools. As society becomes more tolerant of sexually aggressive and abusive language, so this attitude will be communicated to children and young people.”

Mr Sinnott appealed to parents to help schools to encourage more respectful and acceptable behaviour, and not assume that teachers can counter what they accept in their homes.

“Schools have children from the age of 5 for fewer than 30 hours a week, 39 weeks a year. Parents and society in general exert their influences the rest of the time, indeed, the greater majority of the time. They must accept their responsibility to work with schools.”

A spokesman at the Department for Education and Skills said that progress had been made in tackling bad behaviour in schools, and that the passage of the Education and Inspections Act had given teachers “an unequivocal legal right” to impose discipline in the classroom.

“There is no place for bad language in schools, and we support schools in taking a zero-tolerance approach to all forms of disruptive or insolent behaviour. Equally, parents have a clear responsibility to support schools in tackling any misbehaviour from their child.”

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