Think of 1977: the Sex Pistols, Johnny Rotten as the anti-Christ, God Save the Queen in the charts during the silver jubilee summer, the Clash's landmark debut album, the Jam draping the Union flag over their amps, Elvis Costello spitting revenge and guilt, the Ramones and Television and Blondie and Talking Heads coming over from New York. But there was more to 1977 than punk. The charts were dominated by MOR behemoths - Fleetwood Mac's Rumors and the Eagles' Hotel California - and if you were looking for a musical movement to define the year, one that came up from clubs, you wouldn't look to CBGBs or the Roxy. You'd look instead to the records that were played in a New York club called Paradise Garage.
In 1977, disco bestrode the globe like an afro-haired, stack-heeled colossus. There had been disco records before, notably Donna Summer's Love to Love You Baby and George McCrae's Rock Your Baby. But by 1977, disco - dance music's logical next step after the orchestrated, soul-based Philadelphia sound of the early 70s - came to seem less like a series of wonderful flukes and more like the soundtrack to a pop era. The Trammps and Tavares, Thelma Houston and T-Connection, the Brothers Johnson and the Fatback Band were all over the radio and the charts. The real indicator of its popularity was that other artists latched on and began to "go disco", with Marvin Gaye one of the first to succumb with Got to Give It Up, Abba following suit, and even behemoths of white rock - notably the Rolling Stones, Kiss and Rod Stewart - getting in on the act.
The year also saw the debut British chart entries from disco's prime movers, Chic and Earth, Wind & Fire. And, in March, the Bee Gees' manager, Robert Stigwood, made a phone call to his charges that cemented forever the popular perception of disco: he asked the Gibb brothers to provide new songs for the soundtrack to his latest project, a movie called Saturday Night Fever. Finally, there was a bolt of sequencer-driven electro-disco strangeness called I Feel Love by Donna Summer and Giorgio Moroder, one of two trailblazing singles from summer 1977 that transformed the way people thought about popular music - the other being God Save the Queen.
"My vision of the disco era was that it was the most liberating time we ever had in America," says Nile Rodgers, guitarist and co-leader of Chic. Rodgers and his musical partner, bassist Bernard Edwards, were the Lennon and McCartney of the dancefloor. The genre bequeathed countless brilliant one-off singles, but the work of Rodgers and Edwards - whose distinctive sound graced Chic's records and productions for Sister Sledge, Diana Ross, Carly Simon and many more - had the consistency, creative edge and prodigious output of a classic band.
"I'm a child of the 60s," says Rodgers. "I was very influenced by the psychedelic hippie movement, and I was 13 the first time I took LSD. My parents were beatniks, but after they divorced my mom married a white man so our home was very multicultural, open and cool, with poetry, bebop and jazz. And downtown New York was an incredible melting pot of nationalities." But the 1960s, he says, were nowhere near as liberated as the 70s. One reason was Vietnam.
"Disco came out after Vietnam," says George McCrae, whose 1974 smash Rock Your Baby, which sold 11m copies, was disco's Heartbreak Hotel. "There was so much turmoil. People were down and they wanted to escape. It was a dark, terrible time after the civil rights movement. There was a revolution, and disco came at the right moment. It was escapism, like in the 20s after the depression, with the Charleston. People needed to dance. My song I Get Lifted was meant to lift up the people. I had another one called You Can Have It All. There were messages in the music."
Helen Scott-Leggins of the Three Degrees, who made the transition from Philly sound to disco with a string of singles produced by Giorgio Moroder in the late 1970s, takes a slightly different view. She believes the emergence of this new strain of dance music signalled a shift of focus: "Five years earlier it was all about the words, with artists like Sly [Stone], Marvin and Curtis trying to make serious album statements. But during disco, the revolution was in the rhythms."
She also recalls the sense of adventure and mad ambition. "We had fun with the choreography, that's for sure. But some of our outfits - what were we thinking?" she laughs, drawing comparisons between the peacockery of punk and disco. "Punk was an extension of disco; it was just a little more extreme with the piercings and tattoos and different-colour hair. But they had a lot in common. The disco style was outrageous: the bell-bottoms and hot pants, the hairdos, huge eyelashes. When I look back at some of the costumes I think, 'woah, we were running a risk, weren't we?' We could have been arrested!"
For Steven Collazo, the musical director of Odyssey, disco was a time of tensions: between musicianship and mechanisation, between what he calls the "plastic clubs" that played commercial disco and the underground where the harder stuff got aired, and between the latent violence of mainstream hetero discos and the carefree exuberance he witnessed on the gay scene that helped spawn the movement .
"I learned at the 'plastic clubs' to never raise my arms above the imaginary homosexual line, ie above the eyebrows, otherwise the sphincter police would arrest you," says Collazo. But he's got a serious point. "I'm not gay, but I remember one amazing night when I was 18, going to this huge gay club in New York called the Paradise Garage. It was almost like a blueprint for a future society, devoid of social or sexual barriers in an atmosphere of total abandon. I'll never forget that night."
Nor will he forget some of the murkier elements that fuelled disco, such as narcissism and narcotics. "People were like, 'I want to look fly, because I am fly - I ain't got much money but tonight I'm going to put my glad rags on.' There was a sense of desperation in their pursuit of pleasure, and a related upturn in drug use. Cocaine and a lot of other drugs bubbled up into the disco scene, especially the plastic clubs, whereas in the underground clubs it was pot, blotter acid - little sheets of paper you'd stick on your tongue - or more exotic substances like peyote. So you'd have this beautiful symphonic disco music playing, and meanwhile all these people with their metabolism running high, all pumped-up and drugged out. It could get pretty ugly."
Disco's "dark side" can be seen in its most commercially successful manifestation. Saturday Night Fever, released in December 1977, is one of the bleakest mainstream movies ever made in the name of escapist entertainment. In it, John Travolta plays Tony Manero, a blue-collar drone whose balletic grace on the dancefloor is a means of escape from his miserable, working-class life in Brooklyn.
"It was no more or less bleak than the working-class lives of people in Liverpool going out on a Friday or Saturday night," says Chris Amoo of the Real Thing, whose Star Wars-inflected Can You Feel the Force was the UK's finest contribution to disco.
Nevertheless, the image of Travolta as Manero in that suit doing that dance seemed to fix disco in people's minds as comically effete, while the increasingly ubiquitous nature of disco on the radio enraged rock fans, who felt their music was being squeezed off the airwaves.
Hence, the "disco sucks" campaign, barely two years after the genre's emergence. On July 12 1979, DJs Steve Dahl and Garry Meier, along with Michael Veeck (son of Chicago baseball club owner Bill Veeck), staged a promotional event with an anti-disco theme - Disco Demolition Night - between games at a White Sox double-header. The event involved exploding disco records, and ended in a riot. Disco's nadir coincided with probably its greatest achievement: the arrival at No 1 in the charts barely two weeks later of Chic's Good Times, the track that begat rap, sampling (nowadays, Chic are more sampled than James Brown or Kraftwerk) and the polished R&B of today.
For Tavares, whose music featured on the epochal Saturday Night Fever soundtrack, Rose Royce and the other acts, disco is full of happy memories: of winning Grammys and being chased down the street by excitable fans, of being right there at the centre of the disco storm.
But for Nile Rodgers, there remain mixed feelings about the period Chic dominated with their "diatonic, cool chromatic chords", harmonically complex melodies and disco symphonies influenced by Prokofiev and Ravel. A period during which he and Bernard Edwards, as the Chic Organisation, wrote and produced 16 albums, made the biggest-selling single in Warners' history (Le Freak) and, virtually on their own, turned disco into an art form.
"We provided the soundtrack for a new, upwardly mobile, black middle-class," he says. "But we always subverted the message. That's the paradox of Chic: we had this fantasy of jet-setting disco superstardom, and later we lived it. But remember where I came from - I was a subsection leader of the Black Panthers, and I was passionate about this radical movement.
"Before long, though, we became successful - very successful - and I would have said it was devastating but I weathered it," he says of Chic's punishing schedule and attendant distractions. "The lifestyle of excess took its toll on us physically as well as mentally - that was pretty apparent. The problem is we became accustomed to success. And then came the backlash ." He says of the "disco sucks" period: "I don't mean to be a conspiracy theorist but I was there, and it was like we had the plague. It was horrible."
And then he remembers that "amazing universal movement" and the album Chic produced for Diana Ross in 1980, Diana ("It was so angular, dark and avant-garde - listen to how weird it is") and a recent New Yorker Top 10 of the Most Influential NYC bands ever and suddenly disco doesn't seem like a dirty word.
"Where were Chic in the list?" he savours the question one more time because he knows the answer, and it's a good one. "Above the Ramones, man. Above the Ramones."
· The Best Disco in Town tour, featuring George McCrae, Rose Royce, Tavares, Odyssey, the Three Degrees and the Real Thing starts in May. A Chic box-set will be released by WEA in May.