ROCK RIFFS / Dud, dud, duh . . .: 25 years ago a hotel caught fire and the ultimate riff emerged from the smoke. Roger Glover of Deep Purple looks back

Dud, dud, duh. Dud, dud, du-duh. Dud, dud, duh. Dud-duh.

Tomorrow is the 21st anniversary of the invention of the most often played (some might say the easiest to play) riff in rock. On the night of 4 December 1971, Deep Purple watched as the Casino Theatre in Montreux burnt to a char. They were due to start recording their album Machine Head in the building the next day. So moved were the band by the event, that they wrote 'Smoke on the Water' on the spot.

'Smoke on the Water' inspired a whole generation to pick up the guitar. Slash of Guns N' Roses, Adrian Smith of Iron Maiden and Billy Duffy of the Cult have all admitted that they first stretched their fingers across the strings in an attempt to master the song's booming drone. Tomorrow, to commemorate the song's lasting influence, Ian Gillan and Roger Glover of Deep Purple will present a Harp Rock plaque to the mayor of Geneva, on the site of the most famous fire in musical history. Here Roger Glover remembers the events of that evening:

'I can recall it in excruciating detail. We were there in the first place because we wanted to record our album in a live situation. We had heard there was a good hall, with good acoustics, good vibes, in the Casino at Montreux. Claude Nobs, who was running the place, said we could have it for a month, as it was closed for the winter season. So we took the Rolling Stones' mobile studio there and got ready to roll. There was one last show before the place shut down, by Frank Zappa. We watched the show for about an hour, then all I can remember was some sparks up in the ceiling, which was a sort of bamboo. We learned later that some guy in the crowd had fired a flare gun into the wiring up there.

'Anyway, Frank made an announcement that everyone should leave. It was very orderly, but in the melee, I lost the other members of the band. So I went back inside and just stood looking at Zappa's gear because he had synthesisers, which were new in those days. There didn't seem to be any sign of any fire. I stood for a few minutes gazing at these strange objects with knobs on, then went back outside. Suddenly the whole place went up.

'We all retired to this hotel, on the other side of Lake Geneva, and we watched the fire burn from there for about nine hours. The place burnt to a crisp, all Frank's equipment included. It wasn't a good time for Frank: later that week in London some guy got up on stage and threw him into the orchestra pit and he broke his leg.

'Well, that night, the image, of the pall of smoke over this serene lake, stuck with me. And I woke up in the morning with the title in my head: 'Smoke on the Water'. I told Gillan about it and he said it sounds like a drug song, and we don't do drug songs, it doesn't sound like Deep Purple. But I wrote it down on a napkin anyway.

'Claude Nobs moved us into another theatre in town called the Pavilion and we started work. Ritchie (Blackmore) came up with a riff and we were looking for a title, so I said it sounds like 'Smoke on the Water', why don't we write a story song about the events of the evening? As we worked, Ritchie perfected the riff, but the hall wasn't sound-proofed: it was one in the morning and we were keeping the entire town of Montreux up; the roadies were blocking the doors against the police.

'Then Claude put us in the Grand Hotel, which was being re-decorated. We put mattresses on the windows to try to muffle the sound. We made the album in the corridor, with the mobile studio parked in the hotel car park. 'Smoke on the Water' was just an album track. But the song's lasting success is that gloriously simple, yet truly original riff. Every person I have ever met that ever played guitar has told me it was the first thing they could ever play. That's quite an honour. With me, by the way, it was 'Peter Gunn'. '

(Photograph omitted)