Teachers are cracking down on bullying in schools but still find it hard to deal with homophobic abuse according to the Anti Bullying Alliance.

Data obtained by the Evening Standard showed school exclusions rose in 17 boroughs and went down in only five. There were wide variations between authorities. Children were suspended or expelled for bullying on 860 occasions in London schools last year, up 52 per cent from 567 in the previous 12 months.

Simon Blake, spokesman for the Anti-Bullying Alliance, told the Evening Standard: “There is sometimes reluctance for people to acknowledge that there is an issue of bullying. There isn’t a school in the country, as far as I know, that doesn’t have some sort of bullying that they have to address at some particular time. It is not something to be ashamed of.”

However, he pointed out that homophobic bullying, when children use the word ‘gay’ as a term of abuse, causes particular problems for teachers.

He said: “It’s clear that you can’t say racist things but you can get away with saying, ‘You are gay’. People feel less clear or less confident about addressing it.”

Head teachers said the figures showed schools were taking an increasingly zero-tolerance approach to bullies.

All schools must have anti-bullying policies and appoint a senior teacher to co-ordinate them but critics say that too many schools still refuse to accept that bullying is a problem.

A spokesman for ChildLine warned that it was not just the bullies who were being excluded.

He said: “Often the children who are being excluded are the ones that are being bullied. They are trying to take matters into their own hands and are being excluded for that.”

He said that expelling a child for bullying would not solve the problem and recommended ‘restorative justice’ in which a victim confronts the bully in the presence of teachers.