Why are American adolescents fifteen times more likely to turn to murder than their European counterparts?
Miserable teenagers sulk behind slammed doors in countless British bedrooms. Some are even wrapped in black clothes and trenchcoats, but they don't shoot people. Why not? The simple answer is also the most obvious: they haven't got guns. In this country it's only grown-up criminals - such as the Rochdale gang that was ambushed on Friday night - who carry AK47s.

Europe does have some teenage killers. In 1996 two Parisian teenagers enticed a third into a sexual trap they had seen in a film, then stabbed him to death with knives they had hidden under the blankets. The Belfast pair Colin King and Adrian Wilson were 16 and 17 when they murdered a pensioner in 1994. The boys kicked and beat 83-year-old Bessie Robson, stabbed their victim and set fire to her home. Then they went for kebab and chips. Learco Chindamo was 16 when he murdered the headmaster Philip Lawrence in 1995, and acted as part of a gang that modelled itself on the Triads.

Horrifying though these stories are, they remain rare. According to the Home Office there are 76 juveniles serving time in British prisons for murder; in contrast 260 are locked up in US federal prisons, with at least a thousand more in state penitentiaries across the nation. The majority shot their victims while trying to rob them, rather than in a fit of teenage angst. Intelligent, alienated gunboys such as Eric Harris and Dylan Klebold tend to blow their own brains out as a finale to their slaughter.

In Britain moody misfits are more likely to kill themselves than go on the rampage. One explanation for this difference may be the contrasting role models that prevail on either side of the Atlantic: the Outlaw and the Outsider. "America has always glamorised outlaws," said the Gothic horror singer Marilyn Manson in an interview long before it emerged that his music had inspired the killers of Columbine High. "It's a statement of my culture."

The Outlaw as a mythical figure has his origins in the Wild West as a fast-living, fast-shooting rebel on the edge of society. When he wants revenge, he gets it. His spirit inhabits Marlon Brando, James Dean, countless rock stars and modern icons such as the late gangsta rapper Tupac Shakur. He is Charles Bronson in Death Wish, Michael Douglas as the nerd who goes wild in Falling Down, and, notoriously, Leonardo DiCaprio shooting up a high school in The Basketball Diaries. He's not often a girl, except Winona Ryder in Heathers and the eponymous Thelma and Louise.

What these figures all have in common is a gun. "The substantial recent rise in US homicides by young people can be attributed almost entirely to firearm possession," say the experts behind Antisocial Behaviour by Young People, a major international study published by the Cambridge University Press.

"Juvenile homicide is very rare in the United Kingdom," say the authors, a child psychiatrist, criminologist and social psychologist. The figures are similarly low in every industrialised country outside the US. "The number of cases per year over the past two decades has been of the order of only some two dozen."

That's two dozen more than the victims would have liked, but we should be grateful - the US rate for murder by young people is at least 15 times higher. The strange thing is that over the past 50 years every country in the West has experienced a huge increase in juvenile delinquency - along with a rise in drug and alcohol abuse, depression and suicide - but only in America has there been a phenomenal rise in the number of adolescents killing people.

In Europe, the teenage rebel is not the Outlaw, but the Outsider: a pale and melancholy youth, a dreamer who turns in on himself when he realises that the world is a cruel place. He can get angry, like Jimmy Porter in Look Back In Anger or Mick Travers declaring war on his school in If ... but most of the time he just sulks or dreams of suicide.

His texts are L'Etranger by Camus, anything by Sartre and, of course, The Outsider by Colin Wilson, a guide to the literature of alienation that was published in 1956 when the teenager was just emerging as a cultural force.

So far gangs of disaffected British boys have tended to experiment with drugs, sex or petty crime rather than mass murder. Like their American cousins they egg each other on, offer approval for activities that society frowns on, and sometimes drive one of their number to go too far. A 15- year-old pupil at Eton who played a "fainting game" with his friends every day between supper and prayers was found hanging dead in his room in February.

Generally, the Outsider is more of a danger to himself than the outside world, unless his peers mature and leave him even more isolated, a lonely man with dangerous fantasies. We should be wary of feeling safe or smug. Handguns were banned after Dunblane, but there is nothing to stop an English version of the Trenchcoat Mafia reading internet sites to learn how pipe bombs can be made from domestic ingredients. Any teenager with a computer and a phone line has access to racist, pornographic and ultra-violent material, and to explicit instructions on becoming a kamikaze killer.

The computer games, albums and videos that so excited Klebold and Harris are in our shops now. American culture is in danger of suffocating our own - and if it ever comes to a fight, the Outlaw will just blow the Outsider away.