Yesterday's Evening Standard carried a moving article from Dr Christian Jessen, about a school friend who hanged himself because of homophobic bullying. Sadly, we know from many news stories around the world that Dr Christian's story isn't unique: gay young people often find themselves excluded, abused and attacked, to the point that many of them take their own lives.

News stories, of course, only give part of the picture. The full scale of homophobic bullying in Britain is today laid bare in a report from Stonewall, The School Report 2012, based on a national survey of over 1,600 gay young people by the University of Cambridge. The findings make distressing reading: a quarter of gay young people say they've attempted suicide and over half have self-harmed, including cutting or burning themselves. Alarmingly, more than half of gay young people say they're homophobically bullied, one in six saying they've been physically abused. And 6% have received death threats.

Schools should be safe places where pupils flourish and teachers help them to excel. All too often, though, gay pupils walk through their school gates sweating with fear. Three in five of them even say teachers who witness homophobic bullying never intervene. And the problem doesn't stop with direct bullying. Almost all gay young people have heard homophobic language ("that's so gay" or "you're so gay"), but only 10% say teachers challenge it.

It's alarming that any teacher would treat homophobic language as 'banter', but sadly there are some people - including prominent broadcasters and journalists - who suggest it's harmless to use 'gay' to mean 'rubbish'. There is, of course, a very simple objection to that: no-one accepts casual racist language, so why should we accept casual homophobia? Would it be inoffensive for young people (or DJs) to start saying "that's so Asian," or "you're so black" when they mean "that's crap" or "you're a moron"? Of course not.

We can treat weak arguments with the scant respect they deserve, but anyone who suggests we shouldn't worry about playground taunts is colluding with bullies and spreading misery. More than four in five gay pupils say homophobic language distresses them. In schools where such language is never challenged, the rate of homophobic bullying stands at 68% - compared with 37% in schools where homophobic language is always challenged.

The consequences for gay pupils of bullying are severe. Nearly half of gay young people who've been homophobically bullied have skipped school, and a third change their educational plans because of it. Added to the clear mental health risks, The School Report draws a very clear conclusion: any failure to deal with homophobic language or bullying puts young lives and futures at risk.

The good news is it's not difficult to deal with homophobic bullying in an effective way. Stonewall works with thousands of schools around Britain who make sure they provide safe learning environments for all pupils. Whether that's by making sure incidents are dealt with quickly, broadening the curriculum to include gay issues or inviting gay role models to talk to young people, the outcome is always the same - a better school for everyone. Over the five years since Stonewall's 2007 School Report, homophobic bullying overall has fallen from 65% to 55%. Action works - but inaction has terrible consequences.

Dr Christian's story about his late friend isn't unique. But with better school leadership and continuing support from the government to put an end to homophobia, we're hopeful those sad stories will eventually be a thing of the past.

Follow Wes Streeting on Twitter: www.twitter.com/wesstreeting