There's no doubt that a Friday afternoon slot at a Glastonbury recovering from a torrential rainstorm is a tough gig for Fleet Foxes. Their eponymous debut album has been rightly bathed in acclaim, but its currency is blissful, bucolic folksiness: with the best will in the world, a bespattered crowd staring glumly down the barrel of yet another weekend trudging through mud and sleeping under damp canvas is perhaps not the most receptive audience for a selection of songs about the unmitigated wonderfulness of the great outdoors.
And so it proves. In truth, it's not really the songs' subject matter that's the problem so much as their subtlety. The performances are note-perfect, their harmonies gorgeous. However, the band look deeply ill-at-ease on the vast Pyramid Stage, and their music struggles to hold a crowd reeling not merely from the inclement weather but a baffling, unscheduled, interminable preceding set from Pharrel Williams's funk-rockers N*E*R*D, who turn up late, then charmlessly refuse to vacate the stage ("you paid 200 dollars to see a full show," shouts Williams by way of explanation, blithely overlooking the fact that the crowd contains not a single person who's paid to see NERD at all).
In different circumstances, Fleet Foxes might sound fantastic but, White Winter Hymnal aside, they struggle to draw the audience's attention from the more robust entertainment provided in their midst by two filth-caked men cheerfully beating each other about the head with what seem to be petrol cans filled with cider.
No such problems for Lily Allen, blessed with a catalogue of jaunty hits expertly retooled for a festival audience – "Come on you ravers!" she bellows as Smile surprisingly mutates from pop-reggae into frantic drum'n'bass, displaying an ability to project a hugely likable personality to the back of a vast audience. After Fleet Foxes' visible unease, there's something hugely appealing about Allen's self-confidence. "Help me out with the second verse!" she cries midway through The Fear: this seems deeply ambitious, given the unwritten rule that festival audiences invariably only know the first three lines of any given song, but they turn out to be word-perfect.
She dedicates Fuck You to the BNP ("those bastards") and encourages the audience to sing along with middle fingers raised, performs a fantastic cover of Britney Spears' Womanizer – the original's blank facade replaced by a knowing swagger – and offers an insight into the impressive modernity of her family, mentioning the presence of her grandfather stage left, then performing It's Not Fair, a pretty blunt song about male sexual inadequacy, underlining its reference to fellatio with a quick mime.
Elsewhere on Friday evening, Lady Gaga once again demonstrates her steadfast refusal to allow gimmickry to overshadow her important musical message, shooting fireworks out of her bosoms and playing piano while standing on one leg, her posterior exposed to the elements. In fairness, it smacks less of the usual tiresome attention-seeking than a concerted effort to create a splash of clubby glamour in distinctly unglamorous environs.
Meanwhile, given the reverence in which their back catalogue is held and their spotless live reputation, the recently reformed Specials are about as close to a guaranteed success as Glastonbury gets, aided by the fact that they seem to have grown old with an impressive grace. There's an intriguing disparity between their music's grim subject matter and the jubilation with which it's received: never have so many songs about nuclear war, recession and the inherent ghastliness of late-70s Coventry sounded so celebratory.
By contrast to the Specials' sure-thing status, headliner Neil Young arrives trailing a 40-year reputation for unpredictability: he's been on relatively crowd-pleasing form recently, but as any long-term fan will tell you, what Young has been doing recently is no guarantee as to what he'll do next.
A certain trepidation might explain why the audience takes a while to warm to him, but as it gradually becomes apparent that he's going to roll out the classics, the response becomes more fervent, his performances increasingly tumultuous, the endings of every song drawn out into ever-longer, ever noisier codas. By the time he performs Rockin' In the Free World, his ornery old face has been split by a huge grin: he keeps returning to the chorus over and over again, organising the crowd into an arm-waving mass. When the song finally ends, and the crowd roars, Young grabs the microphone and roars back at them, his fists raised in triumph.
An encore of the Beatles' A Day In the Life is even more spectacular. It concludes with Young ripping the strings off his guitar and beating it with a microphone stand, before running to the back of the stage and unexpectedly performing a vibraphone solo. It sounds slightly bathetic, arriving as it does on the heels of a blizzard of feedback that feels like the end of the world: you rather get the impression that he just doesn't want to get offstage, and having rendered his guitar unplayable, is desperately casting about for something to do. Improbable as it may sound given his grouchy reputation, Young appears to be having a Glastonbury Moment.
Saturday dawns with Tinariwen, the cyclical grooves and call-and-response vocals of their Tuareg desert rock sounding oddly soothing as the sun continues to shine. Spinal Tap pay a rather glowing tribute to the recently departed King Of Pop – "if it 'adn't been for Michael Jackson, there would never 'ave been a Spinal Tap," offers Nigel Tufnel – and bring on Jamie Cullum, the latest in a long line of special guests keen to perform with the world's most famous parody rock band: alas, the audience seem less impressed by the appearance of the boyish jazz pianist than they are by the arrival onstage of an inflatable model of Stonehenge.
But the real surprise of Saturday afternoon is delivered by Dizzee Rascal, who draws an unexpectedly vast crowd. You might reasonably expect his sound to chafe against the dopily benign atmosphere of Glastonbury in the sun: despite his new-found ability to lodge himself at the top of the singles chart, it still sounds abrasive. Indeed, it's probably the most challenging music that emanates from the Pyramid Stage all weekend, but the rapper appears to have matured into a fantastic, engaging live performer, couching his stew of harsh beats and samples and bleak lyrics – "let me take you down to London city, where the attitude's bad and the weather's shitty," snaps one song – in shameless crowd-pleasing, including at one juncture, an appearance of the time-honoured cry of "oggi oggi oggi". The audience goes berserk.
The kind of person who bemoaned Jay-Z's appearance at Glastonbury last year, and views the appearance of urban artists on the main stage as an unnecessary distraction from the festival's true calling to promote indie and classic rock, might note that when Dizzee Rascal's set ends, the audience goes altogether, leaving Neil Young's sometime cohorts and Woodstock veterans Crosby Stills and Nash performing to a sparsely-populated field. Stephen Stills takes a photograph as he walks onstage, presumably in order to show friends at home what a distinctly underwhelming Glastonbury crowd looks like.
It seems probable that most of the audience has headed off in the direction of the Dance Arena, in the vain hope of seeing La Roux. Dubstep DJ Skream's remix of her hit In For The Kill has already provided the highlight of his Friday afternoon set, but the audience for the genuine article spills so far out of the tent that, on its fringes, it's literally impossible to see or hear anything of her performance. People stay nonetheless: if you're looking for a symbol of her rise, here it is.
Back at the Pyramid stage, Kasabian do their spirited best, but there's no upstaging Bruce Springsteen, even when he's obscured on the video screens by a giant banner emblazoned with the words I LOVE SAUSAGE. You could argue that what he does is pretty hokey and histrionic – "we're building a HOUSE made out of HOPE!" he cries at one juncture – and there seems to be a feeling that he might have peppered his set more liberally with hits, but it's hard to deny his ability to project to the back of a vast crowd, honed as it has been by decades playing the world's biggest venues.
He swings around his mic stand like a pole dancer, dons a Stetson for the finale of Outlaw Pete, plunges repeatedly into the audience and steals their banners – sadly, I LOVE SAUSAGE remains tantalisingly out of reach – tears telephone directories in half, inflates hot water bottles until they burst, etc etc. He opens with Joe Strummer's old song about Glastonbury, Coma Girl and the Excitement Gang, which frankly could have been written for him.
Virtually everything else he plays has a communal air-punching quality, an air of charged triumphalism (Workin' On A Dream manages to maintain this air even during an extended whistling solo, which is no mean feat), and the climactic numbers – Born To Run, Dancing In the Dark, Glory Days – are triple-tested and infallible. Glastonbury, understandably, eats it up
The big winners: three performers who grew in stature
La Roux
La Roux's success was hardly a surprise, given that her single In for the Kill is currently the third biggest-selling of the year, but the size of the crowd she attracted to the Dance Arena was confirmation of how big a star Elly Jackson has become this year.
Neil Young
A genuinely remarkable, tumultuous performance from rock's most unpredictable old-stager. Not a man famed for being easily impressed by festivals – he famously called Woodstock "shit" – Young looked moved by the crowd's response.
Dizzee Rascal
It wasn't a breakthrough moment as such – he's just had two No 1 hits in a row, so he's hardly wanting for public acceptance or attention – but nevertheless, the sheer size of the crowd and its reaction confirmed the East London rapper's arrival as an improbable mainstream star.
• This article was amended on Tuesday 30 June 2009. In the article above we mistakenly stated that a banner said 'I love sausages', it actually said 'I love sausage'. This has been corrected.
