The Eighties have — like the stack-heeled Seventies before them — been repackaged and filed away as an era of Duran Duran, Dynasty and mobile phones the size of a fridge. Just how it felt to live through the decade if you weren’t a plumber on two grand a week or a character in Less Than Zero — in fact if you were just a mere pop fan — is explored in two forthcoming events.

The American experience is laid bare in American Hardcore, a movie about the likes of Black Flag and Minor Threat, punkers who laid out the rules for grunge, emo and beyond. The British underground of the period is less cool, yet equally influential. One of its milestone moments was a cassette compilation called C86, given away by NME in 1986, containing 22 tracks of what came to be called “indie” music. Back then indie was an abbreviation of independent, a mark of your outsiderdom — you had no dealings with major labels such as EMI or CBS, you were answerable to no one.

A week of gigs at the ICA ran in tandem with the cassette’s release; this weekend there is a 20th-anniversary celebration of the event featuring groups that inspired C86 (Subway Sect, Aztec Camera), some that were part of it (the Pastels, June Brides) and latterday acts that draw deeply from it (Magic Numbers).

Its roots lay in the moribund British pop scene of 1983. The boom that had created New Pop (ABC, Human League, Soft Cell and other post-punk subversives) had inadvertently also spawned super-sanitised acts such as Howard Jones, Nik Kershaw and Paul Young. In those desperate times Lloyd Cole looked like a genuine contender.

What had been a thriving, ever-mutating underground scene three years previously was reduced to a few brave souls who persevered in the face of an increasingly bland and compliant pop landscape.

Alan McGee was one of those who persevered. He had moved to London from Glasgow and started the Living Room club — upstairs at the Adams Arms in Fitzrovia — in 1983. From London came the Loft and the June Brides; from Scotland the Pastels and the Jasmine Minks. All shared a scratchiness, an air of solidarity and an ear for a great tune. Relocating to Chalk Farm in 1984, the Living Room became the hottest venue in town when a quartet of East Kilbride miscreants called the Jesus and Mary Chain made their messy, deafeningly loud debut on McGee’s label, Creation.

The sound of these groups was raw, the influences were Warhol’s Factory, the Byrds, Buzzcocks, Ronettes and Shangri La’s. Creation led the way and by mid-1985 we were in the middle of a minor revolution, time-capsuled by NME’s cassette a few months later.

The Manic Street Preachers’ Nicky Wire said recently: “In the mid-Eighties everyone was a socialist”: the independent, proto-indie C86 scene was definitively anti-Thatcher and anti-corporate. It created its own parallel universe of fanzines, labels and distribution. Groups were groups, never bands (which was a “rockist”, corporate hippy term). Major labels were a no-no, and the new compact disc format was definitely out. Going to the opposite,

DIY, extreme, groups put out flexidiscs instead, a cheap, disposable format that somehow stated their Marxist principles.

But C86 was DIY out of necessity. For most groups there were no jobs, no cash, no choice but to do everything yourself within your means. The look of C86 was second-hand charm. Johnnie Johnson of the Siddeleys aspired to look like Marlene Dietrich. Other girls opted for the Leslie Caron look in The L-Shaped Room, a beatnik Audrey Hepburn. Boys sported the quiff — part Morrissey, part Albert Finney — or the fringe/moptop, pioneered by Orange Juice’s Edwyn Collins. The ultimate role model, for boys and girls, was the Jesus and Mary Chain’s young drummer Bobby Gillespie. Truly, it was an asexual scene.

Like far-left factions, groups that had much in common built up petty rivalries. The June Brides and the Jasmine Minks were the biggest names at Alan McGee’s Living Room club and couldn’t stand the sight of each other. Some found the Wedding Present too macho, others considered the Pastels too fey. The Soup Dragons were condemned as bandwagon jumpers. Some groups on the NME compilation (the McKenzies, A Witness, Stump) were genuinely dire, but attitude over ability often won the day.

This was a generation weened on punk ethics without the “year zero” albatross. If these one-chord wonders couldn’t capture that Phil Spector thunder in the confines of Alaska Studios — a dank railway arch behind Waterloo station — they were happy to try.

By 1987, though, a lot of the impetus was gone. What had seemed like a movement that could challenge the majors, as punk had done, dissipated when those same majors signed up and de-balled some of the bigger names, such as the Bodines and Shop Assistants. Primal Scream aside, very few groups lasted. The immediate future of pop turned out to be nothing to do with C86, or even guitars, but had been brewing in Detroit and Chicago’s bedrooms and clubs — house and techno were the new punk.

Viewed from 20 years away, C86 feels like a great British DIY boom in the tradition of skiffle or Merseybeat. Like its predecessors it was in the vanguard of a revolution rather than the revolution itself. More obvious with the passage of time is that, with the honourable exception of the Postcard label, it was the starting point for indie music. It lit the touch paper for the Stone Roses, then Oasis and eventually all manner of million-selling acts.

The sound — buffetted and no longer sounding as if it was recorded in a garden shed — has become the mainstream. Armchair revolutionaries now have MySpace to do the job of the fanzine. Yet, listening to the new CD86 compilation, there is a real sense of urgency in the music, love and hate in equal measure. Its perpetrators may not have manned the barricades in their anoraks, but C86 was a political education.

C86 — Do It For Fun takes place at the ICA, SW1 (020-7930 3647), Friday 27 and Saturday 28 October, featuring clips from Hungry Beat, Saint Etienne’s documentary about Eighties British underground music, to be released in 2007. www.ica.org.uk. CD86 is released by Sanctuary