Pendulum, Wembley Arena

Next time BBC2 want to do one of those periodic “what happened to the white working class” documentaries, they could do worse than come to a Pendulum gig. The crowd at Wembley Arena last night were defiantly not “studenty” as many for post-rave music acts can be, and neither were they multicultural; in fact, switch the haircuts and outfits around and you could pretty much transplant the same set of people back 30-odd years to an early Iron Maiden show. This was a 21st century heavy metal crowd through-and-through – not fashionable, not refined, but ready to get involved to the maximum extent possible.

Once a drum'n'bass trio from Australia, Pendulum have expanded via the addition of an English MC, Welsh guitarist and American drummer to become a hyper-modern rock phenomenon. For many, as the drum'n'bass scene lost touch with its early 1990s roots in London's black music community, the description of its increasingly unfunky beats as resembling heavy metal was considered an insult. But Pendulum seized on this similarity, and noting the way that electronic acts like The Prodigy and Nine Inch Nails were connecting to rock audiences worldwide, they crafted a sound that has become more popular than pretty much any of their drum'n'bass contemporaries.

It was clear before the band even appeared on stage that they were no longer a club act in any sense: this was not about immersive dance grooves, it was a show. We just caught the end of the support act - the rather impressively shouty Londoners Hadouken! who it seems are shaking off their cheesy "nu rave" tag and operating simply as a fierce electro-enhanced rock band  - then the warm-up DJs were relatively quiet and played uncomplicated tracks, building tension rather than providing entertainment in their own right. The crowd, while spirited and rowdy, essentially milled around and chatted rather than engaged with this music, knowing that everything was geared around Pendulum's arrival. And when they did take the stage, the volume suddenly at demolition level, that milling crowd transformed utterly into a mass moving in unison, a truly awesome site to behold.

The band kicked straight into their signature sound: relatively new track “Salt in the Wound” is angry, rigid drum'n'bass with blaring electronic funk riffs and fizzing guitar layers, over which the band's MC Ben Verse (pictured above) exhorted the crowd to action. “What you give us, we give back, you understand?” he yelled, and in response they poured all the energy they could into slamming into one another, the men among them tearing their shirts off, the women screaming and waving glowsticks. In the next track, “The Vulture”, the line “overboard, under pressure” leapt out: it may be built on synthesisers but this is music for releasing frustrations just as straight-up heavy metal is. Projections of scorpions and cockroaches crawling on circuitboards - like fellow arena rave band Magnetic Man's "I am a bug in this global community" lyric - spoke of willing disruption of routine and escape from mechanised, automated lives.

They are clearly sophisticated musicians, but in every track, Pendulum are about pressing every possible button to get adrenalin flowing. This is the music the Futurists dreamed of. Their cover version of The Prodigy's “Voodoo People” (a track they remixed in 2005) sums it up: every synth sound - played by Rob Swire (pictured left) on a synth/guitar hybrid - is like a klaxon, every bass note an explosion, every drum rhythm a collective panic attack. They have learned the lessons of rave music to bring soundsystem values to a heavy metal audience, and it was very clear from the sound they made that their tracks are constructed first and foremost for the show. What might sound hectoring or annoying heard on record sounds simply mighty on the arena speakers with the audience's energy feeding back to the band.

Inevitably this constant, relentless peak level of energy could get a bit wearing, even as different songs brought in elements of grunge, techno and - in tracks like “The Island” and “Encoder” - the bleakly epic 1980s new wave of a-ha or The Cars. Or rather, it could get wearing for the merely curious listener; but this wasn't played for voyeurs or critics, it is played for fans. Contra the received opinion that the iPod generation are into a bit of everything, Pendulum's fans are real fans, who have clearly pored over every word to every track, and who know precisely when to hold back and when to go mental once again in the live setting.

Those of hip or refined sensibilities are wont to find Pendulum rather gruesome, and well they might. The sweaty, borderline homoerotic aggro of the moshpits in the middle of the crowd is not pretty, and the pounding and reliance on big riffs in the music has that classic metal mix of technical over-attainment and sonic crassness – and yet when you're there in the midst of it, it's incredibly hard not to crack a grin as yet another gigantic bass note shakes the arena and the lasers blast out from the stage. With neither the self-pity of grunge nor the disgusting spoilt child sense of entitlement of its other predecessor, over-Americanised “nu metal”, Pendulum's formula is a refreshing take on the age-old catharsis that heavy metal has always represented, and it's easy to see why those legions of hardcore fans love them so. Their sound may be very different, but like that other Australian-UK hybrid "band of the people" AC/DC all those years ago, Pendulum have created a sound that seems straightforward but which nobody else can do with such impact.

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