To say anticipation was high would be like saying war is stupid. Radiohead, in their absence from the drab musical canvas of these past few years, have created a salivating expectancy that reached pay-back tonight.

In a magnificent tidal wave of celebration, the spellbound Royal Festival Hall audience were regaled with a two-hour sonic tour-de-force, as the band, baring ten new tracks, suggested a legend-enforcing return may already be sealed.

The grandly modernist venue, with banks of seated onlookers and jutting box-seats, was perhaps as wise a venue to make their return as one could imagine, allowing the crowd to be visibly engrossed by a left-field new direction bereft of choruses, structures or true precedents.

Of the new tracks, most displayed a desire from the band to eschew fundamentals such as verse-chorus-verse, with many locking-into repetitive, darkly resonant grooves, as the tension built and the musical explorations unfolded. Vocally, there was also a fascinating control of Thom Yorke's voice that was invariably more atmospheric than lyrical.

Opening with the edgy 'Optimistic', founded on insistent, tribal drumming, there was a graphic sense that witnessing this return was indeed a privilege. A scorching rendition of 'Bones' and a placid but no less compelling 'Karma Police' followed, but, as was to be expected with the follow-up to OK Computer not arriving until October, the new material hypnotised like a rattlesnake about to strike.

'Morning Bell', introduced as 'a song about amnesia', featured Yorke on Rhodes piano, as a jarring drum-beat and a mesh of guitar histrionics built to a wall of relentless tension. The gloriously nail-biting outro to 'Street Spirit', was followed by 'Talk Show Host' and new track 'National Anthem'. Featuring a hard, disturbed bass-line drilled throughout and dislocated samples, Yorke's vocal squabbling struck home the complete lack of chorus to accompany the mantric music.

After a snagged version of 'My Iron Lung', another new track - 'In Limbo' - was revealed, the crowd still reeling from the overload of unheard tracks, previously only discussed in hush tones or via computer connections. More down-beat than the other new material and featuring Yorke rattling away on tambourine, the song boasted the kind of abstract musical breakdowns more readily associated with post-rock and again showcased the irrelevancy of parameters in Radiohead's new world order.

A disarming and still heart-busting 'No Surprises' then segued into 'You and Whose Army', seemingly a bitter tirade against the British government. Yorke, again on piano, with Colin Greenwood on double bass, dedicated the track to Tony Blair, before spitting-out lines such as 'come on you and your cronies….if you think you can take us all on.' 'Dollars And Cents' followed, another magically paranoid blend of wailing vocal atmospheres and guitar.

The irresistible salvo of 'Exit Music', 'Lucky', 'Airbag' and 'Just' all displayed Radiohead's embarrassment of riches, with the band clearly revelling in their return and the constantly thunderous approval, which by now found much of the venue standing in engaged awe.

With the crowd actually more on all-fours than their knees, 'Everything In Its Right Place' closed the set, finding Johnny Greenwood - a constant livewire of floppy fringes and flailing guitars - and O'Brien seated front of stage, drawing projectile, twisted sounds across the venue from keyboards.

On their return and following a dedication to the organiser of Meltdown, legendary avant-garde crooner Scott Walker, 'Egyptian Song', a plaintive piano confessional, and 'Knives Out', were played. These were again displays of wonderfully stratospheric rock, which shot by in snatched moments of brilliant wonder. Indeed, a truly tangible grasp of how good the band were tonight may only be realised when the new record – rumoured to be called Kid A - is actually at arms length.

As the gig drew to a close, and typically magnificent renditions of 'Fake Plastic Trees' and an impossibly seamless 'Paranoid Android' were launched, the band even found time for comedy, with O'Brien retelling the mating practice of Chinchilla's. "The female pisses on the male if she's unsatisfied by him when they're having sex," he explained, while apologising to his father for such a crude observation.

A second encore, featuring a desolate and  moribund 'How To Disappear', closed the set, and the band were gone, smiles surely sliced across their triumphant faces. The new album is clearly going to take the band further out than the more inaccessible moments from OK Computer and may thus shed some fans, uncertain at such a potentially dumfounding approach.

Whatever. Tonight Radiohead finally allowed visitors into their closely guarded lair, in which we witnessed a peerless performance from a band with fire in their hands and whirlwinds in their heads. Inventive, challenging and jaw-droppingly exciting, Radiohead also sent out a vitriolic warning shot to 99 per cent of their 'contemporaries'. It goes something like this: 'WAKE-UP!! YOU'RE DEAD!!!'

-Ben Gilbert