Revelations: Ralph Steadman, Louisville, 1970

"DO YOU want to meet an ex-hell's angel who shaves his head?"

Being in America to look for work, my reply was yes. That's how I found this buddy, this soul mate, Hunter S Thompson; our assignment was to cover the prestigious Kentucky Derby in Louisville. There was this 6ft 6in guy with a chiselled bone head - it looked like a bullet - set on shoulders that didn't need any more muscle. Hunter could have been an American footballer. He had huge feet size 12 or even 14 - in these flat plimsoll-type things he used to wear. I've always tried to find a pair of shoes to suit me, but he found one early on. Hunter found out everything early on; he wanted to be a great writer but was rejected by the Athenaeum Literary Heritage Club of Louisville. So he was home to enact some kind of revenge. He didn't want a photographer, he wanted an artist who could find the face of Kentucky. I thought: Jesus, he's lived a totally different life to me. I was 33; most people would be in their stride by then but I wasn't. But Hunter had been told I could give as good as I got, and I did.

I climbed into his red whale of a car, with two buckets of beer on ice behind the front seats, and went to meet his brother. So far I had made no sketches, or notes, too intimidated to do either. But my head was buzzing with strange impressions. I pull back, mentally unwinding a spring. What I don't realise is just how intently I am watching someone, fascinated by a blemish on their nose or the way an eye works. I thought drawing was a bona fide activity and in England people treasure caricatures of themselves - perhaps the ruder the better, because you've got to make them laugh. What I didn't realise is that in different cultures, and Kentucky is a different culture, it's an insult. They are quite likely to ask you to step outside, and beat the shit out of you. I started drawing Hunter's brother and made it darker and darker and more hideous as lines covered lines. Hunter started fidgeting and making lame excuses until he told me I had a nasty habit. I asked him what he meant? "You keep doing filthy drawings of people. They are beginning to look at you and become horrified, unable to believe it's really them that you're drawing. It is obscene; you've got to stop it!" In fact, Hunter had to Mace a restaurant in Kentucky so we could escape alive. I remember a black tube and a fine hissing sound. My eyes began to sting and everybody screamed. Hunter yelled at me to get out! What he did was even worse - all I do is look at people. But he saved me. It was the first time I realised that what I do can be construed as a rather unpleasant habit. How dare I make these rather presumptuous comments about somebody I'm staring at?

The act of Gonzo might be just as mindless as soccer hooligans but Hunter and I went out of our way to actually do something - making out that we were bona fide journalists covering the Kentucky Derby. We got in because I was speaking in my very proper accent telling officials I'd come all the way from the London Times. It was a completely irresponsible way of going about journalism - no story became a story. Hunter ended up writing about what happened to us; he hadn't even started his writing while I was doing my drawings. We turned failure into a virtue - that was Gonzo. Hunter and I are chalk and cheese - that was the bond. Although entirely different, I was watching people in a way he was leeching into. I was leeching on to his use of language. Two different types of leeches doing the same thing.

Hunter also taught me that when I was doing something outrageous to double the outrage. Together we slipped in between the boats in the America's cup to write: FUCK THE POPE along the side of one of them with a spray can. We did have some noble purpose, though it was a jailable offence. These boats were manned by rednecks, some of them Catholics, and the idea of seeing them sailing into the harbour with that graffito on their hull was a brilliant political concept. We then rushed back to our boat and let off distress flares up into the bay, to symbolise our failure, and set some yachts on fire. It deflected attention, and we were able to get away.

I had the idea that there was a wicked world out there, my mother defended me so well. Hunter would criticise me for being so English and "nice" - it's a horrible word. I needed to meet somebody to blast me out of that cocoon. It took me a long time to reach the frame of mind where I decide the image - irrespective of the story that I'm illustrating. I don't give a shit if somebody understands it or not. I like it, I appreciate it and if I'm enjoying it - someone else will too. That's something else I learnt from Hunter: "if you're chicken-livered, forget it. You'll never achieve anything. But if you want to take the ride, you pay for the whole ride." The edge can be very creative. It made me realise who the real enemy are; I know who I'm after. Previously my anger had no purpose or direction. I chose to draw one person over another normally out of the desire to throttle them. Not a murderous thought, just that I couldn't stand the way their nose twitched; how some people moved their mouth was infuriating. I was going through life unable to stand the sight of people. Meeting Hunter S Thompson made me laugh at it. By easing off, I began to do outrageous things with my cartoons instead.

If I go on making mischief, I think it will be more in books - I'm not very keen on the fish-wrap approach of newspapers. If I'm doing something I want it to last, so people can look back at an opinion from that time and discover that it may still be relevant. But it would be funny if someone tried to wrap fish and chips in my new book, perhaps I should buy a portion and eat them out of it! That's Gonzo!

I have curbed my tendency to stare, judge and hate people partly with the help of therapy, because I began to think it was me that was the problem. I did three months; strangely enough the therapist's name was Dr Thompson... I think it would be worse if I stopped drawing, and didn't recycle my observations. It could become very unhealthy - at least now there is a excuse. It's for art, so I can do anything I want. Otherwise I'd be prosecuted as a stalker.

`Gonzo - The Art' is published by Weidenfeld & Nicolson, price pounds 25