‘We went to see Frank Zappa at Montreux casino. But someone fired a flare gun into the ceiling and – whoosh! The whole building went up in flames’

We wanted a more exciting sound than we had been getting in conventional recording studios, so hired the Rolling Stones’ mobile studio for three weeks to record in the Montreux casino. It was 1971 and the night before we were due to begin, we went to see Frank Zappa and the Mothers of Invention play in the casino as part of the Montreux jazz festival, but – as the song puts it – “some stupid with a flare gun” fired into the ceiling.

Sparks came down and everyone had to get out. I became separated from the band so went back inside to find them. The place was empty, but just as I came out something exploded and whoosh – the whole building went up in flames.

We sat in the bar of our hotel a couple of blocks away and watched the plume of black smoke as the beautiful old casino was reduced to charred wood. A couple of mornings later I was aware that I’d said the phrase “smoke on the water” loudly into the room as I woke up. Later, after guitarist Ritchie Blackmore had come up with a mid-tempo riff, I suggested Smoke on the Water as the title of a song about what had happened to us.