North Mississippi Allstars, Borderline, London

North Mississippi Allstars have blues rock in their blood. The band's founding brothers, Cody and Luther Dickinson, have the distinguished Memphis producer Jim Dickinson for a father. and grew up around such luminaries as Big Star, The Replacements andOtha Turner.

So it's no great surprise to find that they play Southern-fried blues rock. And they play it well - so much so that their gig is almost like a potted history of the genre, from straight blues and old-time rock'n'roll, through country-tinged songs to the soloing extravagance of groups such as Lynyrd Skynyrd.

The boys have certainly got the musical talent to pull it off. What they lack, however, is an identity of their own. Clearly enjoying this one-off London date to the full (it's in support of their slightly tinny third album Polaris), they come across as kids having a great time, but with little to communicate.

It's not individual charisma that's lacking. The giant bassist Chris Chew pulls hilarious cartoon expressions, Luther Dickinson hams up his solos by mouthing along to the notes as though he's playing air guitar, and Duwayne Burnside... well, his teeth are gold, for a start.

But the most striking band member is the drummer, Cody Dickinson. For most of the show he wears an expression of pure terror. Only when he and Burnside swap roles does the concert get interesting. With a contorted face, he whines and wails with rough-edged gusto. His is not the prettiest voice, but it's far more individual than Burnside's blues-man huskiness or Luther's dull drawl. For his next trick - and he grins madly at everyone as he does it, as though he really does believe he's a magician - Cody plays the washboard. Splendid.

But it's only during these couple of numbers that the Allstars appear to have anything of their own to offer. The rest of the time, the packed Borderline watches respectfully, but never really gets jumping. This is typical of introverted, hipper-than-thou London, but it's true there's no need to get excited.

Rock music thrives on the sense of danger and rebellion it conveys. If the Allstars had invented this music, it could sound just the same and be infinitely more exciting. But playing straight blues rock in 2004 is deeply conservative, and that's all these guys do. Covers of standards such as "Sitting on Top of the World" blend in fine with the band's own material. If you told me "Never in all My Days" from Polaris was written 40 years ago, I'd believe you. Maybe they'd take that as a compliment. Maybe they'd be better off in a tribute band.