Keith Richards has defended his use of heroin.

The 69-year-old Rolling Stones rocker - known for hits including 'Angie' and 'Brown Sugar' - said the deadly class A drug, which he gave up taking regularly over thirty years ago, was part of his ''protestant work ethic'' and helped him write songs.

He told Men's Journal: ''I've got to confess, I was very interested in what I could take and what I could do.

''I looked upon the body as a laboratory - I used to throw in this chemical and then that one to see what would happen; I was intrigued by that. What one would work against another; I've got a bit of an alchemist in me that way. But all experiments must come to an end.''

Keith doesn't believe the drug use did any damage, claiming it made actually him work harder.

He continued: ''If I stayed awake I got a few more songs out of it. It's like [former UK Prime Minister Winston] Churchill said about alcohol, 'Believe me - I've taken a lot more out of alcohol than it's ever taken out of me!' And I kind of feel the same way about the dope and stuff. I've got something out of it. Might've pissed off a lot of people!''

Keith also said he ''hates'' rehab clinics and instead preferred to cut back on substances instead of ''giving stuff up.''