Even without Ian Dury, the Blockheads are loved as only a gaggle of fiftysomething Essex cocktail-jazzers can be - with logic-defying fervour. Something of Dury's peculiar charisma appears to have rubbed off on his band, judging by thewhoops that greet their arrival. As they take their places on the poky stage, unresplendent in ponytails and loud shirts, the audience elbow forward until they are nearly on stage themselves. Either they are getting into position to get a good look at Robbie Williams, in case he drops by (he doesn't), or they are bent on soaking up the Blockheads' blokey vibe at close range.

At a guess, it's the latter. Yelps erupt when a piratical character steps up to the mike, and this is only road manager Derek the Draw introducing the band. The really riotous behaviour starts when the Blockheads plunge into the squawking Come and Find Me, and a couple of beefy fans break out air saxophones, swinging them wildly as the band segue into Reasons to Be Cheerful.

Vocals are shared between original Blockheads Chaz Jankel and John Turnbull, and guest Phill Jupitus, who reads the words to Dance Little Rude Boy, The Ballad of the Sulphate Strangler and Hit Me With Your Rhythm Stick from sheets of paper. He makes a credible stand-in: close your eyes as he intones, "In the wilds of Borneo, in the vineyards of Bordeaux", and it's as if Dury himself is mugging it up.

But Jupitus's presence also highlights the relative weakness of the songs from Dury's final studio album, Ten More Turnips from the Tip, which comprise half the show. Dury himself might have made Sulphate Strangler less of a woolly jazz racket, and put hair on One Love's pallid loungey chest. Without their frontman, the Blockheads are merely an exceptionally good pub band. This isn't idle criticism, as they are contemplating a return to full-time playing. If so, they should consider installing 1950s rocker Wee Willie Harris on vocals. This sexagenarian idol of Dury's turned up mid-show to sing one number: tuxedo lapels flapping with exertion, he brought the house down. Now that's a star.

·The Blockheads play the Ashcroft Theatre, Croydon (020-8688 9291), tonight, then tour.