People are always asking me whether I regret leaving the Rolling Stones. I make no bones about it - had I remained with the band, I would probably be dead. I was having difficulties with drug addiction and couldn't have lasted. But I'm clean now and have been for years. My life is so much better now than being a drug-ravaged member of the Stones. So no, I don't regret leaving.'But people who really know me ask another question - whether I regret joining the Stones. To me, that's far more astute.

When they asked me to come to the studio in 1969, I thought they just wanted me to play a session. I sort of liked them, but was never passionate about the Stones. In some ways I liked The Beatles more. At the first session, I overdubbed the guitar on Honky Tonk Women, but I thought they were all a little bit vain and full of themselves. After doing guitar parts on three songs, I said to Mick Jagger and Keith Richards, "If you guys are just going to sit and mess around, I'm going home. I've got things to do." I told them to give me a call if they wanted me to do anything else. The next day, Mick called and asked if I wanted to join. He came and picked me up in his Bentley. I wasn't impressed by all that and I think they kind of liked that attitude.

My drug use began as an occasional recreational thing. I never thought I would get addicted. But by the time I returned to London in 1973, I'd become more and more dependent. I was using every day.

I was a bit impulsive back then. I had a reputation on stage of being quiet, but off it I wasn't. We used to fight and argue all the time. And one of the things I got angry about was that Mick had promised to give me some credit for some of the songs - and he didn't. I believed I'd contributed enough. Let's put it this way - without my contribution those songs would not have existed. There's not many but enough, things like Sway and Moonlight Mile on Sticky Fingers and a couple of others.

When I left, they cut off my money for a year, just like that. But I had to leave because I was frustrated. I had a creative relationship with Mick, but I was also bored for a lot of the time. I wanted more and they wanted to remain the same. I also wanted to deal with my drug problems. I believed if I removed myself from that situation I would sort myself out.

After leaving the Rolling Stones: My father was dying of liver cancer and was in terrible pain in hospital. He said he knew I'd been using drugs and asked if I would ask the nurses for stronger painkillers. I did and they gave him morphine. I sat there trying to balance the irony of the situation.

After moving to Los Angeles in 1990: I joined the line of junkies. I was a virtual down and out. My lowest time was in the clinic on Christmas Day. A nurse gave me a tumbler of methadone and said, "Have a nice Christmas." I told her there wasn't any Christmas for junkies. I decided to go back to England [in the mid 1990s] to find a cure, however painful.