I'm in a Rock'n'Roll Band, BBC Two

This new series proposes to examine the individual roles played by the members of successful rock groups, but you could tell there was trouble in store from the narrator's opening question: "What is the DNA of a great rock'n'roll band?" Like the rest of this first programme, which tried to draw up a job description for lead singers, the question didn't quite make sense. Shouldn't it have been "What is in the DNA"?

It turned out to be the latter, but the more snippets of interview, archive material and horrible cartoons last night's film shovelled into the mix, the more it demonstrated that there was no way we were ever going to get definitive answers. That was instructive in itself. It reflected a basic truth about rock music, which is that singers and bands become legendary because they invent a unique identity which enthralls an audience. They don't understand how they do it, and 999 out of every 1,000 bands fail. Simon Cowell might be able to invent prefabricated phenomena, but he'll never create The Clash. Come to think of it, where was Joe Strummer in this programme?

Thus, every time I'm In... turned the spotlight on some preening rock legend or other and tried to draw instructive lessons from their life and career, it merely came up with another individual with a different set of characteristics. Many singers have been more conventionally "good looking" than Mick Jagger, but he created his own niche by combining athleticism and sexuality with formidable organisational powers and an accountant's brain. Dave Grohl of the Foo Fighters has a knack for making informal contact with a club audience or a sea of faces in a football stadium, but admits he has no comprehension of how David Bowie can instantly turn a festival crowd into his own personal cult of worshippers. Radiohead's Thom Yorke hangs off his microphone like a starving refugee and makes moaning noises, whereas The Doors' Jim Morrison could (so they say) hypnotise his audiences into a collective erotic trance.

You have to give the show credit for doing loads of interviews, but having bagged them, they didn't know what to do next. You'd get a droll nugget from Alice Cooper about what really happened the night he was supposed to have slaughtered a chicken onstage, or Juliette Lewis talking about how the lead singer is usually an unstable egomaniac who knows nothing about music, and then the narrator would ruin it all by saying, "Jim Morrison was like some kind of Oedipal stormtrooper." They even tried to tell us that Nirvana's Kurt Cobain was a singer "totally without artifice," as if Kurt was just singing in the bath every time he went onstage.

It's rock music's misfortune to have become old enough to be turned into a minor branch of sociology, in which all its original meaning has been regurgitated by geeky rock-spotters as fourth-hand soundbites and received wisdom. They'd have done far better here to pick one singer and use him/her as guide and presenter, which might have brought some coherence to what was, frankly, a shambles. Bit late now, I suppose.

The Rolling Stones play Brown Sugar