Essay of the week by Sylvia Patterson

In 1986, I went to my very first music festival, the main one in the UK calendar among only a handful of others, the one then officially known as the Glastonbury CND Festival. The headline bands were art-rock titans The Psychedelic Furs, goth-pop ghouls The Cure and - oh dear - Level 42.

But for any young indie kid in the mid-1980s, it was the smaller, preciously-adored "John Peel bands" which dominated the psyche, and so special delirious devotion was saved for The Housemartins, We've Got A Fuzzbox And We're Gonna Use It and Half Man Half Biscuit, the surreal-pop Birkenhead visionaries who serenaded the summer sunshine with a song called All I Want For Christmas Is A Dukla Prague Away Kit, B-side of their 1986 debut single, The Trumpton Riots (from debut album, Back In The DHSS).

The music, though (as the hippies before us foretold), was always secondary to the true Glastonbury soul, located "out there" in the endless acres of psychedelic dreamscape populated by jugglers on unicycles dressed up as trees, windmills tilting into the ecologically utopian future, convoys of travellers passed out in front of threadbare teepees and the nebulous belief in something called The Revolution, as twitchy young men loitered by ditches saying something equally nebulous about "black ash, trips!" in a selection of regional accents.

Glastonbury 1986 did what Glastonbury had always done - offered not merely a holiday from mainstream reality but a portal to infinity, a parallel universe of alternative possibilities where "vibes" alone would definitely save the world. A three-day ticket, meanwhile, cost £17, which was just the ticket for a sizeable proportion of the 60,000 attendees who were then on the dole in Fatcher's beleaguered Britain (Billy Bragg was playing too), while many paid nothing via nimbly jumping the easily penetrated fence.

If Glastonbury 1986 felt like running away with the circus, as the festival always had done since its inception in 1970 (the year T.Rex headlined and "the counterculture" ruled), it was also undeniably 1986 - and if you weren't there, you didn't know what it looked like, sounded like or felt like, enthusiastically documented as it was only by the weekly music press several days after its close, the ink evaporating off the voraciously-read pages onto your still festival-grubby hands Twenty three years later, and what we now know only as "Glasto" (£152.50 per ticket) is a mind-blowing affair for exactly the opposite reason. It's now the very definition of mainstream culture, even if the contemporary mainstream has become an increasingly bewildering concept. With the identity of this year's headliners alone, any "legal highs" purchased from shiny-faced potion vendors would not be the reason you'd no clue whatsoever which decade you were actually living in; was it the 1970s (Neil Young) or the 1980s (Bruce Springsteen) or the 1990s (Blur)?

The clues you existed, in fact, in 2009 were the new attractions sprung across the cityscape colossus populated by 150,000 people which "out there" has now become: queues snaking towards the Orange help centre to charge up mobile phones; state-of-the-art teepees for hire for £800 per weekend; 24-hour ATMs; a Smoothie Shack; a Pret A Manger; an NHS stall offering a free chlamydia test kit; and, for the first time, an Oxfam stall offering a "restyle service" from celebrity stylist Mrs Jones (specialist seamstress to Kylie Minogue and The Killers' Brandon Flowers) resulting in scores of lookalikes of Springsteen, Lady Gaga and Natasha from Bat For Lashes. Which is lot less like living in a parallel universe and more like going to a festival in a Topshop suddenly missing its roof.

The festival which once defined individuality, in fact, now brings to mind a scene from The Life Of Brian, where hundreds of Brian's followers shout in unison "we're all individuals!" and a lone voice chimes in from the distance with a singular "I'm not".

The BBC, meanwhile, now covers the festival with the kind of rigour and resources it used to reserve for the Olympics, Wimbledon and the World Cup. This year, to much subsequent derision, 400 staff from the BBC covered the event, producing 111 hours of TV, 60 hours of radio, 600 online pages and 57 hours of online video across BBC 2, BBC 3, BBC 4, Radio 1, 6 Music and 5 Live, plus interactive "red button" options and a constantly updated website. Which is far less "on-the-run from mainstream reality", more "living inside the festival equivalent of a colossal Big Brother house".

Unlike the "entertainers" in the Big Brother house, however, almost nothing at Glastonbury, or any other widely broadcast festival, including our own T in the Park, is ever subjected to widely broadcast criticism. The personnel of Radios 1 & 2 normally perched on a comedy papier-maché mushroom in the Wellington boots du jour, identically convinced every single aspect is "cool", "wicked" and "marvellous", a curious consensus across generations which the public fully endorses.

How, really, can 150,000 music fans all love Born To Run? It was a boulder-sized cheeseball of sax-rock bluster on its release in 1975 and remains as much today. And can you truly love Born To Run, Blur's Parklife and Tom Jones's cover of EMF's Unbelievable at exactly the same time with exactly the same gusto while, for much of the shiny-haired contemporary crowd, none of it was "your" music in the first place? Evidently so, because none of it really matters as long as you got to "be there" and had a rollicking good sing-song - and you can sing along to anything if it's famous enough because the dominant cultural equation remains famous = good. Which only gives pause to miss the mighty John Peel and his uniquely withering ways even more than we do already By the time T in the Park arrived in 1994 (starring Oasis, Blur and Primal Scream), music festivals has already changed dramatically. Late 1980s/early 1990s mass-rave culture created a simultaneous mass-drug culture and the best way to experience all of that was staggering through a field clutching at chums, amid a thrum of repetitive beats. T in the Park had its Slam Tent (and still does) while dance music festivals sprung up like toxic toadstools in a swamp of hedonistic sweat, from The Big Chill to Creamfields to Gatecrasher.

Pop culture across the spectrum- pop, rock, indie, rave, hip-hop, R&B and all their permeations - crept steadily overground. Corporate sponsorship became acceptable, brands were on their way, New Labour and it's "we're all middle class now" agenda took up residence in Number 10 and rock 'n' roll took up residence in the newly-invented tabloid pop columns and soon onto the front pages - with the trials of Oasis and Blur through the mid-late 1990s, a cartoon caper Liam Gallagher has since identified as "the best soap on the telly".

Just as football was now populated by Roy Keane's "prawn sandwich" brigade, so music festivals became increasing polite, though more importantly increasingly more "pop" (and therefore more attractive to women). The grassy knolls of new festivals such as Virgin's "V" were now festooned in stripy deckchairs and picnic hampers, while headliners Travis in 2000 delivered a spirited cover of Britney Spears's Baby One More Time.

Celebrity Culture had dawned, as had the most voracious consumer culture the world has ever known, buoyed through this decade by the New Labour "dream" of the lie of infinite credit, an era which one member of those politically-driven Housemartins from 1986 (Paul Heaton, also ex-Beautiful South) would go on to describe in 2008 as "The Golden Age Of Flash".

Since 2002, Glastonbury had also employed its impenetrable 12-foot Superfence, the festival which once refused to let police in now keeping the lawless out - though this was also a response to the Roskilde festival tragedy in Denmark in 2000, where the sheer weight of numbers saw nine music fans crushed to death.

By 2001, the iPod was invented, followed by iTunes in 2003, and the way we found, consumed and appreciated music fundamentally changed forever. It heralded a hitherto unthinkable new musical landscape where barely anyone under the age of 20 has ever paid for music, even as music has never been more accessible - all forms of music, from every era were suddenly a click away, generally free, all the time, forever.

No wonder the festival experience is now identical to the iTunes experience, a planet-sized pick 'n' mix bag of whatever you randomly fancy without knowing, or needing, any explanatory context. It is both a miraculous progression and the very thing which renders music almost meaningless, because your investment is almost negligible - financially, emotionally, culturally, even politically - so all you're left with are the 21st-Century connections of sonics, visuals and flamboyantly choreographed "moves".

No wonder, for the Greatest Hits Generation, that pop is their dominant force, the last few years seeing a relentless spectrum of diverse pop music magpie-picked from across several eras and the best of it predominantly female. From the vocal dynamics of Adele, Duffy and the still-missing-in-action Amy Winehouse to Lily Allen's rude-pop, Lady Gaga's art-pop, the Ting Ting's rhythmic shouty-pop and La Roux's preposterous 1980s-pop, the girls are comprehensively eclipsing the indentikit boy guitar bands we've come to know as "landfill indie".

Glastonbury, naturally, being the festival grandpa, has long resisted supposedly trivial, novelty pop music but that, too, is changing. In 2005, Michael Eavis made a seismic effort to show willing; had Kylie not been ill and accepted his headline offer she would've been the first woman to headline the Pyramid Stage in the festival's then 36-year history. In a couple more years, then, who knows?

Perhaps the NME will fold, unable to sustain itself on those dreary indie boys and the pop girls will finally rule, the NME stage across the nation's festivals replaced by The Sun's Bizarre Stage, headlined by Girls Aloud, while Amy Winehouse catapults herself off The Other Stage and Beyoncé shimmies the Pyramid Stage' asunder, just as her husband Jay-Z did in 2008 as the very first hip-hop headliner. The chances are looking likely, as the 73-year-old Eavis retires in 2010 and hands Glastonbury on to his daughter, Emily, currently aged 29...

Next year heralds Glastonbury's 40th anniversary, and in the passing of those 40 years we can perhaps observe the passing of music as the centrifugal force which sits at the centre of youth culture. Certainly, it no longer defines a generation, which is far more defined by the actual revolution of its communication-changing technology that has, unintentionally, all but obliterated badge-wearing, life-or-death, allegiance-swearing musical devotion.

Popular culture is now, surely, too popular, and therefore so are its reflective festivals, now available to attend from May until September. The once shadowy domain of hippies on drugs is now a cultural kaleidoscope of Top 100 Festival lists, an infinite choice from the corporate-sponsored giants to the relatively new "family friendly" festivals and the tiny "off the tracks" festivals in everglades throughout the UK: a contemporary version of Butlins meets a Village fete and just one more option for a pleasant day out for all the music-loving family.

We're still looking, it seems, for that holiday from reality, but now we're taking reality with us because we're now so pampered we can barely live a day without it. Or at least we think we can't. And if we aren't at festivals to particularly expand our minds, we're definitely there to spectacularly expand our iPods.

Still, come T in the Park next Friday, the thousands will stampede, as ever, and have the time of their lives, as ever. And the rest of us will watch it on TV and perhaps, momentarily, wish we were there.

"There's a good feeling here," said Michael Eavis as this year's Glastonbury was about to commence, "one you won't get anywhere else other than a church. Or maybe a Rotary Club." He certainly wouldn't have said that in 1970.