Drugs. Underage sex. A local gangster. A couple who want to be together, but can’t. A manipulative adult, possibly with a sexual motive. Lots of violence, ideally with at least one death. Here are your ingredients: go and make a hard-hitting teen movie.

The first of these on my radar was Reefer Madness. Made in 1936, it’s the story of schoolkids smoking joints at Mae and Jack’s house. Mae and Jack let the kids party on dope, but have sinister motives and really want sex. Things spiral out of control. Confused boys consume too many drugs.

Passions and jealousy run high. In the end, the hero, Jimmy, shoots a girl.

Next, for me, came 1979’s Quadrophenia. Mods score speed, fight on Brighton beach with chains and knives, have sex in alleyways and, ultimately, kill a man. This sends the hero, Jimmy, into an amphetamine psychosis. Baz Luhrmann got in on the act with his 15-year-old Romeo and Juliet, whose friends have sex, take drugs and fight on the streets. Romeo’s friend Mercutio is killed and that sends ... well, you get the picture.

Which is where Kidulthood comes in. Despite front-page shock stories screaming that every parent should see this movie — a claim made in the 1950s about Rebel Without a Cause — there is little in it that hasn’t been covered in, say, the BBC’s Grange Hill. Katie, a nice middle-class girl at a tough Notting Hill school, is bullied until she kills herself. Her classmates, all roughly 15, get a day off to mourn, but choose to spend it fighting, taking drugs and having sex instead. This being a movie, though, the graphic depictions of sin put Grange Hill to shame. Zammo’s heroin addiction was portrayed by zits and a stupefied expression; Becky (Jaime Winstone) snorts lines of cocaine in loving close-up, having scored the stuff by giving a blow job. Her best friend, Alisa (Red Madrell), is pregnant by wannabe hardman Trife (Aml Ameen) but, like Danny Zuko in Grease, he’s dumped her because she makes him feel embarrassed around his friends.

Indeed, most of the plot lines play out with an awkward predictability. Trife runs errands for his yardie uncle, who initiates him into the “family” at a party where cool, skinny people smoke heroin and Trife is expected to carve up a defaulting junkie’s face with a Stanley knife. This makes him see the error of his ways and run back to Alisa’s arms. Meanwhile, the school bully, Sam (played by the film’s writer, Noel Clarke), is hunting Trife and his two mates Jay (Adam Deacon) and Moony (Femi Oyeniran) for breaking into his house, having sex with his girlfriend and stealing his weed.

So rapidly stacked are the scenes of shock and awe, they become slightly comic. Becky and Alisa snort yet more coke at another older man’s flat. Becky offers anal sex to Jay. Katie’s brother buys a gun from Trife’s Yardie uncle and tries to shoot Sam. The obligatory death occurs. Clarke is desperate to cram in every one of the news cuttings he proudly boasts inspired his script and, in so doing, leaves out basics like character development and believable relationships.

All of this would be fine, of course, if the film were really performing the public service it claims. “The film shouldn’t shock people, because it’s in the newspapers every day,” Clarke says excitedly. Yet this isn’t a documentary for one obvious reason: most of the time, real teenagers do absolutely nothing. Yes, violence, sex and intoxication are the currency when their lives flicker into action. But for all the pappy Lindsay Lohan/Princess Diaries syrup dressed up as shiny-pink teen entertainment, the daily experience of adolescents is like that of a trenchbound soldier: 99% boredom, 1% terror.

And whether it’s the author William Leith, beaten senseless at his public school, or this writer, bogwashed at his local comp, most men fight during adolescence. Countless girls fend off the inexpert groping of pre- pubescent boyfriends and seek the sophistication of an older man. From glue-sniffing to cider to cheap acid and cannabis, teenagers test the limits of their mind’s expansion almost constantly. The only people who should be shocked by this film are people who have never been teenagers.

What Kidulthood does is take all the violence, sex and intoxication experienced in a teenage year and condense it into a single day, because that’s far more marketable than a film about eight kids spending four hours sitting on the swings wondering what to do. And this film is all about marketing. For one thing, it’s partly funded by the Covent Garden clothing label Boxfresh, which dresses every rough, tough, rude kid in its heavily branded hoodies (arguably the most implausible plot point of all, since this year’s hoodie of choice is the sky-blue McKenzie). The director, Menhaj Huda, cut his teeth in commercials and wears that training on his sleeve, although fortunately he zips onto the big screen with confidence and helps conceal the film’s many flaws.

Indeed, cast and crew all excel. Newcomers Ameen, Deacon and Madrell, and the up-and-coming Winstone, take the shaky plot and sell it for all they’re worth. Britain struggles to produce cool, credible teen actors, but almost every youngster here delivers an enthralling, convincing performance that blows the adults — and the script — off the screen. But is that enough? Remember, Reefer Madness was ironically rediscovered by a generation who found its hysterics hilarious. In 2001, it made it onto Broadway as a camp musical; last year, it was remade in high-kicking finery, with Alan Cumming and Neve Campbell. Me, I’m preparing my score right now: Kidulthood, the musical.

I wonder if Boxfresh would fund me?

Kidulthood, Three stars
15, 91 mins