It is, perhaps, hard to explain the great taste and artistic power of Björk when, as tonight, she appears onstage as a giant purple meringue dancing the hornpipe. Hopping onstage in this avant-garde ballerina kit, with red blotches by her eyes and black foliage painted down her arms, she appears to fit the stereotypes used by her detractors: pretentious, kooky, utterly absurd.
Not that Björk or her fans care, of course. Nowadays, the pressure of commercial success seems to have been lifted from her shoulders, and with it any need to rein in her eccentricities. So tonight's show is an extravaganza of colour, beauty, noise and brilliant ideas that conform only to her own unique aesthetic code.
For the most part, it's closer to high art than pop, incorporating performance art, chamber music and radical sound design: the band consists of genius electronica duo Matmos, harpist Zeena Parkins and a string octet.
But it's also intensely human. So while Björk may initially look like a monument to unwearable fashion, the unquenchable life and spirit within her soon makes the alien accessible. 'Pagan Poetry' begins and the music is stately, ornate, but soon there's a great gushing warmth caused by Björk roaring, a capella, "I love him! I love him!" over and over. One song in, and already there's been an authentically heartstopping moment.
Absence of Inuit choir notwithstanding (how many times have I dreamed of writing that!), it initially seems as if the show will be a virtual reprise of her 'Vespertine' performances. In fact, it's radically different: only a couple of songs from that album turn up. Instead, the 'Vespertine' idea - a sort of solemn classical fragility underpinned by volatile, glitchy rhythms - is extended to permeate rarely-visited corners of Björk's back catalogue. So plenty of 'Homogenic' gets a radical overhaul, and the screeching digital jungle that accompanies an encore of 'Isobel' proves that, as her best ever collaborators, Matmos improve everything.
In fact, the brilliance, of Matmos' skittish, squelching, curiously funky music means that, for once, the focus isn't entirely on that extraordinary voice for a change. It's their radicalism which seems to provide an impetus to the new songs, which reveal Björk heading further and more fearlessly into the leftfield than ever before. 'Desired Constellation' is understated, a logical extension of 'Vespertine'.
But towards the end of the set - prefaced by a thumping microhouse version of 'It's In Our Hands', the music gets tougher and more extreme. A shadowy figure behind banks of machines proves to be Björk's old accomplice - and fine solo artist - Leila, adding a massive new dimension to the sound. So something billed as 'Nameless' on the setlist cuts violently between starkness and great rushes of musique concrete, while 'Where Is The Line' pits the sort of smothered hip-hop and crackling noise usually found on Digital Hardcore records against a Schoenberg-esque string arrangement.
It's astounding, and a timely reminder that Björk's subversion of the mainstream has been a much longer and more profound project than that of Radiohead. If 'Vespertine' suggested an introverted retreat, then the next Björk venture looks likely to hook up the prettiness to a compelling new abrasion. Lightweights should stick with their Goldfrapp albums: it may get brutal from here on in.
