I started out, in the mid-'70s, taking photographs of rock bands that I liked but not because I really wanted to photograph them. Initially, I was pretending to be a photographer, simply so that I could go up to the front of the crowd and be a bit closer to the bands. But, I found I was gradually developing an interest in the photos I took.

I preferred that option, where my camera (and by proxy, me) could look them straight in the eye. The way they reacted to me was always interesting. Sometimes hard young men would reveal vulnerability and a softer side. In the case of teenage girls, I often got a fascinating glimpse of the woman inside.

I started out, in the mid-'70s, taking photographs of rock bands that I liked but not because I really wanted to photograph them. Initially, I was pretending to be a photographer, simply so that I could go up to the front of the crowd and be a bit closer to the bands. But, I found I was gradually developing an interest in the photos I took.

Only a very small proportion of us take those excesses with us into later life. In the age before everyone had a camera, it was worthwhile, in my opinion, to record those excesses. Sometimes, many times actually, the young people I photographed were only dressed that way for one night; that one night that they got snapped by me.

Once I became a photographer, it stopped me being scared or intimidated by gangs of young men of whatever stripe. Initially, I could hide behind my camera but eventually I came to realize that if I was polite and friendly to them, then they probably would be to me too - a good life lesson.

The reason why so many of my photographs in the book were taken in stairwells and corridors was that that was the only bit of spare space available and, in some cases, the only place where there was enough light to see anything. Even then, it was often so dark that I couldn't tell which gender my subject was (not that I particularly cared) and too dark, before the era of autofocus, to focus. I had to find a light (or carry a torch) and pre-focus.

Things are very different now because a lot of those little clubs don't exist. In Soho for instance, where nearly half my nightlife photographs were taken, it's rapidly changing. There isn't the same after dark frisson of excitement about the place any more.