RADIO / An accident that waited to happen: Nick Curtis welcomes the late arrival of Michael Wall's Headcrash, after three years in limbo, and says Happy Birthday to Mick Jagger

'I'M GONNA shoot roller-skaters, you coming?' must be one of the best offhand lines of dialogue ever. It encapsulates the grimly humorous, nihilistic ambience of Michael Wall's futuristic Headcrash (Saturday, Radio 3), a weird piece that's languished in the archives since 1986, finally finding a sympathetic slot in the 'experimental' Studio 3 season two years after its author's death.

Strong on mood and stingy with specifics, Wall's post-apocalyptic wasteland is peopled by a mixed bag of creeps, crazies, hitters and bozos. Our 'hitters' are Boy and Yuka, tooled-up and revved-up as they cruise the freeways, blowing away fellow travellers to gain advancement in a bizarre officially sanctioned game.

Yuka (Toyah Willcox) is smothered in bandages because her skin is disintegrating. Boy (Jeremy Flynn) was born in a highway pile-up, could drive before he could walk, and tries to keep a mental record of their life with the archaic words ('mother', 'crime') that pop into his head. Some time later we learn that they're related. But that's about all we learn.

Where and why this wasteland exists, who's in charge and how the game works never become clear. Hints at contemporary relevance and a vague suggestion it's all happening in Boy's head are dangled. But Headcrash decelerates to an almost apologetic halt with Boy becoming 'a real bastard', freed of encumbrances and able to kill with his eyes alone.

Even so, this was gripping stuff thanks to its evocation of the sensations, if not the sense, of a demented future world. Mia Soteriou and David Chilton provided a revolutionary soundtrack, the dialogue constantly underlaid by a driving electro-hum, its rhythm reminiscent of telegraph poles ticking past at speed. The effects - explosions, rat attacks, the scream of rending steel - were laced in to make a superb totality of sound.

Flynn was a little stilted as the confused Boy struggling to impose meaning on confusion. But Willcox was excellent in what was her radio debut, freaking out at the rodents, gleefully dismembering a posse of ambushing crazies, or eviscerating one of the 'Creeps' who enforce the game (an act in direct contravention of the rules, I might add). Of course, the theme of Headcrash is not remotely experimental. From Schwarzenegger to Sam Shepard, the idea has had more mileage than Boy could ever hope to travel. It is Wall's refusal to use the scenario as an obvious metaphor, and the technical excellence of Jeremy Mortimer's production that distinguish it. It's probably what kept it off the air for so long, too.

For the past week, it has been impossible to keep Mick Jagger off the radio. For those who've been living under a stone, that's because it was the Midnight Rambler's 50th birthday yesterday. Gazumping celebrations by two days, Nicky Campbell presented Mick Jagger: 50, Not Out (Saturday, Radio 1), a rockumentary so uncritical and uncomplicated it'll never get repeated in Studio 3.

Factually informative and entertaining, this was unfortunately steeped in the kind of rock lore that's difficult to take seriously in these post-Spinal Tap days. Campbell began by asking if it was time Jagger hung up his mojo, but slid gradually into hagiography as he ticked off all the usual bumps hit by the Rolling Stones. There was the repackaging of the band as satanic southern opposites to the cutesy, Liverpudlian Beatles; the drugs bust and William Rees-Mogg's subsequent Times editorial 'Who breaks a butterfly on a wheel?'; the revelations that Mick was actually quite a nice boy. Satisfaction? Not much.

Listening to this you'd be forgiven for thinking the Rolling Stones were a duo, a sort of Peters and Lee called Mick 'n' Keef. Campbell and producer Kevin Hewlett ignored the other musicians and most of Jagger's private life (except to note that he doesn't like talking about it). Despite the contributions of eminent rockologists it was the comedian and actor John Sessions, of all people, who had the most insight.

Sessions' pinched Scottish drawl analysed Jagger's ambiguous sexual appeal: at the Hyde Park concert, the 'Little Red Rooster' had 'skin like chicken meat', and 'looked like he wanted to be laid by the garrison of a town'. But it was Sessions' mimickry that beautifully deconstructed Jagger's voice into its constituent parts: Cheyne Walk snob, American-inflected bluesman and incoherent cockney lout.

As Sessions said, no one challenges this absurd concoction because he's Mick Jagger. He's a man who made ugliness sexy; a middle-aged hipster in a medium he described at 30 as 'adolescent'; a man equally at home with Princess Margaret as Muddy Waters; half of the best living songwriting partnership and a fifth of the best rock band in the world. In short, he's a star, and as long as he's a star he can keep putting Campbell and the rest of us on.