HE cuts an unlikely figure for a rock star, does Thom Yorke. For starters, he appears to be no more than four feet tall, and his eyes have a puffily new-born look. Indeed, as wee Thom ambled hesitantly on to Friday night's stage, clad in Chaplinesque out-sized trousers and with his sleepy peepers half-closed, you'd have been forgiven for thinking here was one vulnerable laddie who'd tearfully come back down the wooden hill from Bedfordshire for parental reassurance.

In reality, of course, Thom's fey and angelic choir-boy falsetto is driven by a thoroughly adult concern about the state of the world. Similarly, Thom's four Radiohead compatriots manfully operate each song to a dynamic, muscular and no-nonsense formula in which every quiet, pretty, and reflective passage of Thom's vocalising is followed by a ferocious outbreak of post-grunge noise.

In less skilled hands this obvious formula would soon wear thin, but Radiohead have a masterly way at crafting melodic surprises within the limitations they've set themselves. Oh, and they also have Thom Yorke, who on Friday revealed himself to be the most compelling kind of rock star: a likeable, sensible one you can trust.

Sometimes Thom was charmingly self-deprecating. His abstracted dancing style carried overtones of a playground tantrum. Yet he dedicated one song to Lundin Links - ''where I spent much of my childhood'' - without appearing to curry favour with the locals, and untrendily introduced another, Paranoid Android, as a vehement denunciation of cocaine. That's Thom Yorke and Radiohead: grown-up music delivered with an adolescent zest.