"They were very theatrical. Alex Harvey was 40 something, he was an old guy. And - at the time - that was ancient for rock n roll. He won the Scottish Tommy Steele competition in 1957. The prize? Meeting Tommy Steele! What a bizarre business. That was two years before I was born and he must have been in his late teens/early 20s by then. To be in your early 40s and starting out was unheard of. David Bowie and Alex Harvey knew each other, actually: they bonded over a shared love of Jacques Brel. 'Faith Healer' is one of the best things that ever came out of the 70s. And the end triplet of 'Last Of The Teenage Idols' – which is about the competition that he won. That was amazing. I loved his voice: he screamed his way through life. His version of 'Crazy Horses' is hilarious. He did a song called 'There's No Lights on the Xmas Tree Mother… They're Burning Big Louis Tonight'. It was about a guy in the electric chair who takes all the power off the grid on the night of his death. Nobody in this little town in America gets the Xmas lights. What a brilliant idea for a song. It was theatrics and bravado. Alex Harvey was off kilter - it wasn't like The Sweet or Mud, he was musically brilliant."

"There is certainly a rasp to my voice [LAUGHS]. It's not quite as bad as Bonnie Tyler's but it is raspy. Rod Stewart wasn't a big influence on me as a singer though. I don't really sound like anybody. In the same way that Ozzy doesn't sound like anybody or Alice Cooper doesn't sound like anybody. You get these boyband singers now that are all very similar. Even in the old days, you could swap round some of the Motown singers and you wouldn't really know the difference. Singer wise, I loved Mark Bolan; Noddy Holder; David Bowie; Alex Harvey; Russell Mael; Steve Harley; Brian Ferry; Sammy Hagar; Phil Lynott. All that lot go into a bucket but I still don't sound like any of them [LAUGHS]. Mutt Lange was a huge influence on my singing: he can play anything, do anything. He was pushing and pushing. I remember the first time I ever met Lou Gram from Foreigner. He said: 'tell me, did Mutt make you feel like you couldn't sing either?' and this was fucking Lou Gram, right? He'd make you do it again and again. He would push and push until you'd be right on the edge of losing it. Sometimes that worked and sometimes you felt like your spirit was being destroyed. Physically, you're going into spaces in your head and your chest cavity that you've never been. But he would've done it with anybody: look what he did with Brian Johnson, he put him through the bloody ringer with Back In Black but look what he got out of it. And that's why I don't complain. Rod Stewart was the first album I ever bought with my pocket money. The version of 'I'm Losing You' is just genius but my 'in' to that record, as it were, was 'Maggie May' because it was all over the radio at the time. It was rock but it was pop rock: it's not been influential in terms of how we sound but I absolutely love it."