"Relax, don't do it, when you want to suck it to it. Relax, don't do it, when you want to come..." While these words provided ample excuse for BBC Radio and TV to impose a ban on the joyously hypnotic 1983 debut single by Frankie Goes To Hollywood, they also served as a mid-'80s anthem during an era when homo-eroticism became an intrinsic component of the Britpop scene. Thanks to a suitably lewd S&M promo video that, predictably, was also barred from the airwaves, along with a massive marketing campaign that saw kids all over the UK wearing T-shirts with the slogan 'Frankie Says Relax', the band rode a short-lived wave of high-profile controversy. Yet of far longer-lasting impact was the music behind all the hype — a hi-NRG brand of dance-synth-pop that, as crafted by production supremo Trevor Horn, broke new sonic ground, while epitomising '80s excess in all its garish, overblown glory.

Having honed his studio skills with Geoff Downes, when they wrote, performed and produced as synth-based band the Buggles (of 'Video Killed The Radio Star' fame), before also replacing Jon Anderson and Rick Wakeman in prog-rock band Yes, Trevor Horn became a full-time producer in 1981 and enjoyed considerable chart success with pop outfits Dollar and ABC. During the next two years he also co-composed several hits with Malcolm McLaren and Anne Dudley, at around the same time that he and wife Jill Sinclair acquired Chris Blackwell's Basing Street Studio complex. Renamed Sarm West, this also housed their new publishing company, Perfect Songs, and the ZTT record label that they founded with NME journalist Paul Morley and producer/engineer Gary Langan.

In May 1983, having seen Frankie Goes to Hollywood perform 'Relax' on Channel Four's The Tube music programme, Horn signed the band to ZTT. Fronted by singer Holly Johnson, with Paul Rutherford on vocals and keyboards, Brian Nash on guitar, Mark O'Toole on bass and Peter Gill on drums, Frankie had gone through various line-up changes between their formation in 1980 and the John Peel session they recorded for BBC Radio One in October '82. After accepting an invitation from The Tube to perform 'Relax' at the Liverpool State Ballroom in February of the following year, Frankie then included this song in a new BBC Radio session, along with 'Welcome To The Pleasuredome' and 'The Only Star In Heaven', and it was these broadcasts that caught Trevor Horn's attention.

From the outset, Horn focused on 'Relax' as the first single (as well as, interestingly, a cover of Gerry & The Pacemakers' 'Ferry 'Cross The Mersey' which would end up on the B-side of the 12-inch mix). However, initial attempts to record the chant-like 'Relax' with the band members and Ian Dury's backing group, the Blockheads, proved unsatisfactory.

"When I first heard the track, it was a lot funkier than the finished version," says Steve Lipson, whose engineering of the song represented his first collaboration with Trevor Horn. "Trevor's brilliance was to then take it in a different direction and to a whole other level. He really went at it. Frankie were his first signing to ZTT, and he wasn't going to give up until he had a hit."

The producer and/or engineer of artists ranging from Annie Lennox, Grace Jones and Cher to Paul McCartney, Simple Minds, the Pet Shop Boys and Boyzone, Lipson started out as a guitarist and songwriter in a number of different bands around his native London, "nearly getting deals, always blowing it."

It was in 1975 that, fed up with his "terrible" guitar sound, he told a friend named Duncan Bruce that he'd like to become an engineer and learn how to record it himself. Bruce, who recorded jingles, had just purchased a building, and he asked Lipson if he was interested in constructing a studio. Lipson was, and over the course of the next year he put together the Regents Park Recording Company.

"I didn't have a clue what I was doing," Lipson now admits. "I read a few books, talked with different people, bought £15,000 worth of gear, did a bit of building work — with no acoustic treatment — and we opened for business. I obtained a 16-track Unicol tape machine from Command Studios, and the very first session featured a band that had to record a jingle in three hours. I had never recorded anything in my entire life, so I set up however I could, basically imagining what to do, and encountered a problem with the tape machine. When the pinch wheel went in, the tape rode up and down, and half the time it went over the top of the heads. I didn't have a remote, the machine was about 15 feet away from the console, and so I'd go in to 'record', stand by the machine to see if it settled and, if it did, I'd run over to the console, hit the talkback and say, 'Go'. It was a baptism by fire.

"For some bizarre reason, the studio started doing really well, and within six months a band named Sniff 'n' the Tears came in to record an album, Fickle Heart, and I ended up co-producing it just because I...