No future? Punk is still the sound of youth rebellion the world over

On a broiling Sunday afternoon in Kennington Park, south London, a few dozen people are gathered under a large tree. A handful are playing boules and some line up for a three-legged race; most are simply drinking and talking. Yet 35 years ago such an event would have prompted uproar among other park visitors because this is the Punx Picnic, part of a non-profit urban punk festival bluntly called Scumfest.

The picnickers illustrate what a broad church punk has become via its myriad mutations over the years: neither the threat to public morals of old nor an irrelevant retro cult. Although one sports the scarlet spikes of hair familiar from Oxford Street postcard racks, they are a diverse group united only by an unseasonal fondness for black.

To most people, punk may be preserved in the amber of history but to those who attend events such as Scumfest it is very much a going concern, and not one that is simple to describe.

Punk's annus mirabilis, 1977, is as distant from us as the middle of the second world war was to the young Sex Pistols. By chance, it coincided with the silver jubilee, locking Johnny Rotten and the Queen together in a regular cycle of anniversaries until one of them dies. This year, some republicans have mounted an online campaign to get the Sex Pistols' God Save the Queen to no 1; Olympics organisers unsuccessfully approached the band to play at the closing ceremony. To the average Briton, meanwhile, punk is a piece of familiar pop culture bric-a-brac that Andy Radwan, writer, solo artist and veteran of the punk band Eater, sums up as "the three chords, the mohican, the leather jacket and the spitting".

But nostalgia doesn't explain the survival of punk as a sprawling global subculture. There is something there – some irreducible core attitude – that continues to thrive even when Joe Strummer is dead and John Lydon (no longer Rotten) advertises butter. When a musician (or writer, or activist, or fashion designer) uses the phrase "punk rock attitude" we sense what they mean, even if we don't agree with their application. "Punk to me means living by your own politics and doing things on your own terms," says the Wakefield-based "acoustic punk" Louise Distras. "The term has been used very liberally, maybe too much, but I think it all boils down to that one universal idea."

British punk was the product of a specific time and place. In London in the mid-70s, wrote the young Martin Amis, "everything seemed ready for the terminal lurch". Punk was a symptom of that mood of crisis, but from the very start it refused definition. The US punks disagreed with the British punks. The Clash disagreed with the Sex Pistols. John Lydon disagreed with the rest of the Sex Pistols. Some embraced politics, others ignored it; some wanted to return to rock 'n 'roll basics, others to forge bold new styles.

Within a couple of years there were hundreds of bands, each proposing their own version of what punk meant. In late 1977 Crass, whose cottage-industry approach would become hugely influential on future generations of punks, scrawled a resonant slogan on the wall outside the Roxy club in London: "Punk is dead. Long live punk."

So while the Sex Pistols burned fast and bright, the music they inspired continued to mutate in countless directions, including post-punk, anarcho-punk, New Wave, hardcore, grunge and riot grrrl, each one coexisting with other versions rather than erasing them. Outside rock, artists such as Public Enemy, Tricky and the Prodigy have aligned themselves with punk, and punk ideals are as apparent today in a spiky, independent character such as the grime MC Wiley as they are in any rock band.

"I don't think punk is necessarily a style of music," says John Robb, a writer and musician who helps promote the annual Rebellion punk festival in Blackpool. "It's a questing attitude and not just slavishly following the rules. Punk means different things for every person. For some people it's anarchistic, for some people it's leftwing, for some people, unfortunately, it's rightwing and a lot of people in the middle just like the records and have some vague notion that it's travelling in a communal direction."

The paradox of punk is that it fosters both the desire to build a community with like-minded souls, be it via gigs, fanzines or the internet, and the kind of dogged individualism that tends to fracture those communities. In his classic punk history England's Dreaming, Jon Savage calls punk "an international outsider aesthetic: dark, tribal, alienated, alien, full of black humour". Groups of outsiders inevitably create their own outsiders. Passions run high. When Green Day graduated from California's puritanical Bay Area punk scene to playing arenas in the early 90s they became instant pariahs to their old friends.

Robb, an idealist but not a purist, sees value in even the most mainstream manifestations of punk. "If an 11-year-old gets into Green Day, the door opens to this whole counterculture that's just beneath the surface. It's like Pandora's box and a million great ideas come flying out. You think there's only one side to culture and then you find all this great stuff underneath, offering questions and solutions. That's the power of it. Even when people misuse punk, maybe 10% find out what it really is."

If there are many gateways to punk, then punk itself is a gateway to a host of ideas. Despite the popular image of a bunch of straight white men playing loud guitars, punk has often been an unusually progressive arena for women and people of different races and sexualities. Although, as Distras notes, "just because someone labels themselves as punk, it doesn't automatically absolve them of prejudice", the scene inclines towards tolerance and change.

To Mike Sabbagh, an Occupy London Stock Exchange activist who works on the Occupied Times paper, punk represented "baby steps" into activism. "I remember when I was 16 in Detroit, listening to bands like NOFX, Crass and Conflict and thinking: 'I don't feel like a crazy person anymore,' " he says. "There's other people who feel like this and they're articulating problems that I'm only starting to get into focus. It's not just the lyrics that are pushing back against social norms – it's the practice of getting out and publishing your own stuff, making small communities. People really can make a huge difference in music and the shared communities that come out of it."

Sabbagh's Occupied Times colleague Steve Maclean points to the squat-punk scene as a forerunner of Occupy. Many of the more theatrical guerrilla tactics used by activists today have their roots in the punk diaspora of the mid-80s, while in countries such as China, Burma, Indonesia and Russia – where the anti-Putin feminist band Pussy Riot face the threat of seven years in prison for "hooliganism" – punk is still the music of resistance.

"Punk's become synonymous with politics," says Radwan. "Like The Girl with the Dragon Tattoo – she dresses like a punk and she's fighting the establishment in an underground way. That's the image that a lot of people have. The spirit of punk rock is in these movements like Occupy and WikiLeaks. There's more creative things done with it there then are done by the UK Subs playing a few gigs."

This is where Radwan parts company with those of his contemporaries who are still on the road performing the old songs. "Punk rock is not an excuse for 50-year-old men to squeeze into leather trousers and sing Where Have All the Bootboys Gone?" he says. "And if you do think it's a good excuse then you've missed the whole point of punk rock. The punks who are going to [Rebellion] with the mohicans and the leather jackets, there's no difference between them and the people who used to go on those rock'n'roll package tours in the 70s – the people we, as the new kids on the scene, used to take the piss out of. It's embarrassing."

It goes to show that when it comes to the true meaning of punk you are never far from a heated argument. Distras says that she has been criticised both by old punks for playing an acoustic guitar and by fellow acoustic punks for writing strongly political lyrics. "I come across the different factions but I don't even know the names to be honest. It's a bit pointless to be arguing about what punk means when we're all trying to make the world a better place."

This may sound almost hippyish in reference to a culture which emerged in a complicated roar of rage and disgust but even when punks clash over ideals they agree on the fundamentals: self-expression, independence, nonconformity, resistance, a belief in alternatives. While punk's external signifiers are no longer shocking, these core principles continue to inspire new generations. "Mainstream culture tends to eat everything up but I think punk still has the connotations of something subversive," says Maclean, who offers as succinct a summary of the living spirit of punk as you are likely to find. "It is a refusal to accept that this is the way it's going to be."