Simon Price on The Knife: Is this a gig? A performance? Or a rubbish aerobics class?

Their Shaking the Habitual tour will go down as one of 2013's most controversial. But The Knife shouldn't view that as some sort of victory. The Swedish brother-sister electronic duo have moved a considerable distance between the sublime synthpop of 2003's Deep Cuts and the experimentalism of their current album. And while Karin Dreijer-Andersson and Olof Andersson have always used striking visuals, it's clear tonight that the Venetian masks of the intermediary Silent Shout era were merely a stepping stone to something more extreme and, sadly, less satisfying.

The best claim that can be made for this show, executed with a collective called Sorkklubben, is that it "challenges preconceptions of what a concert is". Except it doesn't.

It starts reasonably well. Once the warm-up – an aerobics instructor – has piped down, nine cowled figures appear, like monks beamed in from a visiting space ark. They play, or "play", a light sabre on a log, a laser harp and futuristic maracas. Within three songs, however, they've ditched the hoods, dropped the "instruments" – along with any pretence of playing live – and begun prancing about in glittery masks to a backing track. And so it continues. Sometimes they stand in a huddle; sometimes they disappear. Sometimes there are half-baked projections, or uninspiring lights. I've seen acts on a hundredth of the budget making a better fist of performance art.

I'm no authenticist, but Karin Dreijer-Andersson has a voice that conveys tragedy and heartbreak like few others, and I want to hear it. I'm later told that some of the vocals, drums and percussion are live, but I'm sceptical. On "Ready to Lose", Karin sits at a keyboard and seems to be singing, but I sneak round the back where I can see that her keyboard is a hollow prop. Then we're back to the show, a bad Butlins troupe in Lycra and tinsel. As a piece of modern dance, it's barely adequate. As a Knife concert, it sucks.

Tell people you're going to a Chas & Dave (Concorde 2, Brighton ****) gig, and they smile. The reason, however, can vary. Sometimes, it's fondness at the memory of "Gertcha" or "Rabbit". Sometimes it's a condescending smirk.

But Chas Hodges and Dave Peacock are a fascinating phenomenon: the "novelty" act that refuses to die. (They've retired and unretired three times in recent years). Not only the guardians of a working-class London musical tradition, Chas & Dave are inventors of one, in the shape of "Rockney", their own style (and the name of their record label), which combined old-time East End pub sing-songs with American boogie-woogie. They'd never call it anything as pretentious as "fusion", but that's exactly what it is.

And they are, simply, terrific fun. Chas is the owner of a surprisingly potent rock'n'roll voice in the Noddy Holder envelope, and a fearsome pianist: his knuckles are a blur. Meanwhile, Dave is easily the match of (say) John McVie for musicianship, but wouldn't dream of being showy enough to prove it. They still draw a devoted flat-capped crowd of cockneys and mockneys: the Concorde 2 has to widen its doors to accommodate that big-elbowed, big-kneed walk they all do. And there's an insane pubstep "pie-and-mash-up" of "The Sideboard Song" with a Pendulum track, in which they express indifference as to whether 'ee comes round 'ere at 180bpm.

The peak is a deafening, arm-waving singalong to their biggest hit "Ain't No Pleasing You", a genuinely great rolling blues ballad which, were it written by a Fats Domino, would be venerated to the heavens by the cognoscenti.

One day, when they finally do give it a rest, we'll realise what a peculiarly wonderful thing they were. Until then, Chas & Dave concerts will still be raising smiles, for all the right reasons.

Critic's Choice

The Great Escape, seaside wristband-dash and music biz convention, brings a line-up including Bastille, Billy Bragg, Everything Everything, A*M*E, Chvrches, Deap Vally, Findlay, King Krule, Kodaline, The 1975, The Strypes and Tom Odell to various venues in Brighton (Thu to Sat).