Kim, Daisy And Lewis, Bestival, Isle Of Wight

Ain't no hoedown without Ma and Pa!

It's become a bit of a trend, this whole bring-your-dad-into-the-band thing. The night before, I had watched Mystery Jets' singer Blaine Harrison being royally upstaged by his fiftysomething father's tambourine-shaking antics, prompting a communal "I wish he was my dad" moment in the Bestival crowd.

British siblings Kitty, 13, Daisy, 18, and Lewis, 15, (below) are more old-fashioned, in the sense that the parents (Graeme on the guitar and Ingrid on the double bass) take a back seat. And, unlike Mystery Jets, who exude their own wonky brand of cool, Kitty, Daisy and Lewis are positively Waltonesque. Dad smiles proudly in the background, the kids grin at each other during a particularly tricksy guitar solo, um, Mum pounds the bass...

Apart from the fact, of course, they play the Devil's music: classic rhythm and blues and rock'n'roll covers, impeccably played and sung. It starts with the best-known song of their repertoire - Johnny Cash's "Folsom Prison Blues" - which lures the hungover crowd to the main stage, Pied Piper-like, if only for the spectacle of seeing a bequiffed 15-year-old matinee idol, dressed like an extra from the Back to the Future 1950s prom scene, singing "I shot a man in Reno, just to watch him die..."

They all take turns in the spotlight (after all, good parents never have favourites). Tomboyish Kitty takes on Sonny Boy Williamson's "Polly Put the Kettle On" and Johnny Horton's "Mean Son of a Gun", while her pouting, curvaceous older sister grapples with "Got My Mojo Working".

Are they a novelty band? Sure - and an awesomely cute one, at that. And if that sounds patronising, it's not intended, because their musicianship would put several older groups to shame. The audience audibly gasps as the siblings pull out an ever-increasing number of instruments - ukuleles, lap steel guitars, banjos, accordians, drums, even a spot of naive beat-boxing - and prove themselves to be honest-to-God virtuosos.

Of course, no 13-year-old girl sings like Sonny Boy Williamson, but it's refreshing to see one showing respect for his music, when most of her peers are dreaming about the curly-haired one from The Kooks. It's kids like Kitty, Daisy and Lewis who will keep rock history alive and fresh, with their wide-eyed tributes to its dead visionaries.

Lily Allen may have drawn a bigger crowd at the same stage, but Kitty, Daisy and Lewis were the more likeable of the two acts. One is a charismatic overnight pop sensation of limited musical talent, the other harks back to a time when practice made perfect, and music wasn't just a means to fame. Or maybe Lewis scruffs up his hair and pulls on a hoodie as soon as he leaves the stage. But I very much doubt it.