Dave's tale is legacy of political neglect of young adulthood

It was anchored in a commitment made at the time by John Denham MP, the deputy home secretary (and minister for youth), to combat the social exclusion of young people.

Dave's story was always a poignant one, although he was not an easy individual. He hated all those professionals who "interfered" in his life, including me, although he probably hated me slightly less.

Twelve years ago, Denham had expressed concern that, despite the apparent success of many of New Labour's commendable youth policy reforms - around, for example, truancy and school exclusion, teenage pregnancy, young people in care, and young people not in education, employment and training (Neet) - too many young people were still being excluded from school and slipping into the drugs culture.

Dave was the perfect illustration of Denham's concern. Excluded from secondary school almost as soon as he started, he became embroiled in the drugs culture, as both user and dealer, progressing rapidly from dope and speed to smokeable heroin and crack cocaine. Unsurprisingly, he became entangled in the youth justice system, serving five detention and training orders before the age of 17.

The only thing he stayed connected to in any purposeful way was the youth centre, possibly because his long-standing girlfriend was, with her peer group, a regular there. Dave came away - somewhat grudgingly - on residential weekends, once admiring in a childlike way the steam engine on a miniature railway in Wales. It was a momentary escape from the constant challenges of urban life where street cred and style prevailed above all else.

We did what we could. I had no end of conversations with Dave about his lifestyle, although they were often abruptly curtailed; he "wasn't bothered". We talked about how to deal with his addictions, but he took nothing further. His girlfriend and I met him on his release from young offender institutions. His mother and I concocted all kinds of plans to support him and try to keep him away from the networks where he could access drugs and increase his debts.

Around the age of 17, that support and Dave's natural charm, coupled with his girlfriend's balance of loyalty and ultimatums, helped to extricate him from the downward spiral he had been in for most of his teenage years. Dave got a job and appeared to have left his wayward past behind him. For a few years, he earned money and stayed on the right track. But the work dried up and he slipped back to his old ways. Facebook photos convey very clearly his return to heroin use, although the pictures are that awful form of "heroin chic" - evoking those anti-heroin posters of a good looking young addict that became collectors' items for teenage girls. Dave was always a poseur and usually he did look good.

Dave's situation confirms the need to assess and address youth transitions over a considerable period of time. If the marker for Dave had been aged 20, he would have been proclaimed a success. Despite his lack of qualifications and his criminal record, he was no longer a Neet and would have been lauded by politicians as one of their "hard working" people.

Five years on, that was no longer the case: Dave had returned to being a shirker, benefit dependent and isolated from mainstream possibilities. He didn't bother with Iain Duncan Smith's welfare reforms; he got by on the edge as best he could. By then, his educational failure, criminality and protracted unemployment had taken its toll on his prospects in the labour market. What was on offer was never going to be enough for Dave. Nor was it going to be the right kind of thing: subservience and obedience were not his form.

Many of the political promises in the run-up to the general election were related to young people - apprenticeships, housing, learning, job guarantees. Wider commitments, such as giving mental health equivalence to physical health, will bear especially upon the young. Let us hope some of it will be followed through with concrete action for those who need it most. The prevalence of young people who are Neet and the escalating levels of mental health problems among the young are not, in the words of famous sociologist C Wright Mills, private troubles, but significant public issues. We have a moral obligation to address them.

Dave died of a heart attack just before the general election, at the age of 30.

Howard Williamson is professor of European youth policy at the University of South Wales