“That is so gay” – it’s a phrase heard in classrooms and playgrounds across the country, often said with blissful ignorance of the harm it can inflict on vulnerable young minds.

Leading the crusade against homophobia in London schools is Camden Council, named the capital’s top local authority for tackling lesbian, gay and bisexual (LGB) prejudice in schools by equality charity Stonewall.

From turning the term “gay” into an everyday insult to more overt forms of bullying, homophobia is rife with 55 per cent of gay pupils experience homophobic bullying in Britain’s schools.

But in Camden the problem is being challenged head on.

Sarah Rose, who co-ordinates Stonewall programmes in schools across the country, has worked closely with two Camden secondary schools - Regent High, in Somers Town, and Acland Burghley, in Tufnell Park.

She said: “We encourage the schools that we work with to take a zero tolerance approach to the use of the word ‘gay’ to mean ‘rubbish’. Homophobic language can undermine the confidence and self-esteem of gay young people, or indeed any pupil who is considered to be different by others.

“Having two fantastic schools like Regent High and Acland Burghley working with us is just brilliant.”

Ms Rose explains that homophobia in schools can manifest itself in a variety of ways, from cyber bullying and verbal bullying to physical attacks, all of which have alarming results.

She said: “Homophobic bullying affects pupils’ attendance, their attainment and their aspirations.

“Homophobic bullying also affects LGB young people’s mental health – there are some quite horrific statistics in relation to self-harming and attempted suicides.”

According to research carried out by the University of Cambridge, one in four LGB young people who have suffered homophobic bullying have tried to take their own life at some point and more than half (56 per cent) of these LGB young people deliberately harm themselves.

In Camden, a partnership between the council and Stonewall has ensured each school is provided with resource packs full of literature to help tackle homophobia, including lesson ideas and ways of celebrating difference in schools.

The council has also worked closely with Camden Lesbian, Gay, Bisexual, and Transgender (LGBT) Forum, which takes part in school assemblies and shows its own anti-bullying video Treading on Eggshells in schools.

Ms Rose said: “What’s key is having an inclusive curriculum in schools so if, for example, you’re teaching an English lesson and studying the poetry of Carol Ann Duffy then you mention she’s a lesbian. It’s important to present positive LGB role models in schools.”

Last year, gay British actor Sir Ian McKellen visited pupils at Regent High School and Acland Burghley to commend them for their work as members of Stonewall’s School Champions Programme.

Following the announcement last month that Camden is the best local authority in London for tackling homophobia, and sixth nationwide, Cllr Angela Mason, Camden’s cabinet member for children, said: “I am exceedingly proud that the excellent partnership work by the council, our schools and Camden LGBT Forum has not only been recognised by Stonewall again, but that there is an improvement on last year too.

“This demonstrates our ongoing commitment to tackling homophobic bullying.”