If the Knife's current mission, advertised in the title of the Swedish duo's new album Shaking the Habitual, is to disrupt assumptions, then their first London show in seven years can be judged by the extremity of the audience's reactions. Some are enraptured; others are visibly cross or walk out. You would not be surprised to hear a disappointed fan shout "Judas!" It's like nothing you've ever seen.
Of course, nobody expected singalongs and confetti canons, but they probably did expect something like the new album: dense, challenging, more art than pop. The solemn opener, Cherry on Top, suggests as much, with around 10 figures on stage concealed by hooded robes and dry ice, like some mysterious cult conclave. But it's a red herring. For Raging Nun, the hoods come off to reveal a brightly clad dance troupe banging out a chaotic rhythm on glow-in-the-dark percussion, midway between a tribal rite and the communal dance to Abba in Lukas Moodysson's movie Together. So it proceeds.
It's not the music that's confrontational – even the chewier album tracks acquire vivid techno energy – but the concept. If this weren't a Knife concert but some unbilled display you stumbled across late at night in one of Glastonbury's wilder tents, it would be simply joyous. But because it is ostensibly a gig, it forces you to question your prejudices about authenticity and live performance. Most of the music appears to have been prerecorded. The sounds you hear rarely match the instruments you see being played, if they are played at all. It's almost impossible to locate the core duo of Karin Dreijer Andersson and Olof Dreijer because the vocals are either mimed by different dancers or entirely disembodied. There is ample spontaneity in the anarchic choreography, which often resembles a stage invasion, but almost none in the music.
Should it matter? Why would seeing Olof prod a laptop full of preprogrammed sounds be more "real"? The Knife are admired for warping sounds beyond identification and pitchshifting vocals to blur their gender, so this flagrant erasure of authorship is just the logical conclusion, making avant-garde ideas both provocative and fun. When Silent Shout, one of only three old songs, provides an ecstatic rave finale, its familiarity is a treat – but it's not the point. The point is to be left buzzing with the invaluably rare delight, or in some cases outraged disappointment, of having your expectations turned inside out.
