Ladytron, ICA, London

My favourite band in the world - an irresistible beast

The ICA cinema screen shows a monochrome montage of vintage audio machinery - reel-to-reel tapes, amplifier dials - distorted, twisted, chopped up and re-cut. Then imagery is in perfect sympathy with the six humans stood in front of it, and the noise they are making.

Electroclash came and went, the fashion crowd moved on, and Ladytron - who predated the movement by a couple of years anyway - have survived it, and prospered: Danny Hunt, Reuben Wu, Mira Aroyo and Helen Marnie have slowly but surely gained more respect than any of their (con)temporary peers, and are now rightly revered as one of Britain's finest bands. Not, however, without a few hitches: they were recently rescued from the twin collapses of their UK label (Telstar, where they were always odd bedfellows with Mis-Teeq and a billion Best R&B Ever Vol 2 releases) and their US label (Emperor Norton) by Island Records.

Their staggeringly great third album, Witching Hour - due in August, and already a powerful contender for Album Of The Year - highlights exactly why Ladytron never quite fit in with the Electroclashers in the first place. There's nothing digital on stage or on record: each element, even the synths, are played in real time, by human fingers, and then, just like the retro gear on the screen, manipulated and distorted into something unholy, unearthly, and paradoxically inorganic.

Witching Hour is Ladytron's noisehead record: the glacial elegance of Light and Magic and its lo-fi predecessor 604 has been replaced by a dirty physicality (it sounds as though it has more guitars on it, but this turns out to be deceptive: with Ladytron, when you hear a guitar, it's probably a synth, and vice-versa). Structurally, some of the songs follow familiar patterns - the outstanding "Destroy Everything You Touch" has much in common with their greatest hit, and tonight's encore, "Seventeen" - texturally it's almost unrecognisable.

At first sight, however, everything is deceptively familiar. The utilitarian boiler suit uniforms of yore may have been replaced by funeral-wake evening dresses, and the severe haircuts may have grown out (Mira has cute ringlets, and with her sharp-fringed bob, Helen, who has "CLEOPATRA" Letrasetted onto her Korg, looks as imperious as Queen Liz in the film version), and the guys at the back are still Men In Black.

But from the very first note of this small-venue showcase, it's evident that we ain't in 2002 any more, and that Ladytron intend to drag their back-catalogue up to date to match the new sound: "Cracked LCD", one of the most pristine, elegant moments from Light and Magic is delivered in an at-first-unrecognisable style, turbo-charged and augmented with a high-pitched, soaring drone which recalls My Bloody Valentine.

I like to think that the blank stares and slackjawed silences around me are caused by sheer shock at this stunning reinvention, but alas it probably has more to do with the fact that the crowd is largely made up of record label lackeys rather than true 'Tron fans.

At which point I must lay my cards on the table: Ladytron are probably my favourite band in the world. I occasionally say this about one or two other acts - Super Furry Animals, Dresden Dolls, Manics, The Darkness - but Ladytron never drop out of my personal top five. Later, two friends will tell me they stood at the back, pointing at the stage, saying "See that? Two attractive women playing moody synth music? That's the inside of Pricey's head, right there." As such, it would be easy for me to act the purist and, in a reversal of the folkies who shouted "Judas!" at Dylan for going electric, crucify Ladytron for not being electric enough, but the new Ladytron is an overpowering, irresistible beast.

Indeed, when a souped-up "He Took Her To A Movie" (their debut single, and originally a rudimentary Kraftwerk pastiche) reaches its eardrum-endangering climax amid a warzone of strobes and dial-twiddling, I worry that my brain might be about to explode.

Power on its own, of course, is banal. Anyone can do Loud. Not anyone, however, can do Loud And Clever. Ladytron's musical intelligence is self-evident, but their lyrics are praised less often. Enigmatic vignettes, written with the sparse mystery and bleak romance of a cold war thriller ("a foreign coin in a telephone box, a question mark on a calendar..."), they allow any number of interpretations.

"Seventeen" itself is a perfect example, its haiku-like minimalism - just four lines, hypnotically repeated countless times ("They only want you when you're 17/ When you're 21, you're no fun/ They take a Polaroid and let you go/ Say they'll let you know, so come on...") - inviting you to speculate whether the subject is modelling, pornography, or the trafficking in Russian mail-order brides. The same applies to new single "Sugar", and the "something illicit and temporary" which is being traded: is it sex, drugs, or something else entirely? In this respect, the twin roles of the two vocalists add layers of meaning. Helen Marnie is the singer, delivering straightforward melodic narrative, while Mira Aroyo is more of a commentator, repeating certain lines spoken-word and sotto voce, lending a dark sarcasm to the most innocuous phrase.

Ladytron are at their most enigmatic, of course, when Aroyo sings in her native Bulgarian, as she does on "Fighting In Built-Up Areas", the craziest, noisiest new 'Tron track (and tonight's finale): unless you've spent a significant amount of time in Sofia, your guess is no better than mine.

Those question marks spill over from the calendar, and into my notebook. What do Ladytron mean? What are these rogue electro freaks - disappeared up Noise River like four Colonel Kurtzes - trying to tell us? And when it sounds this awe-inspiring, does it matter?

s.price@independent.co.uk