Many nightclubs from this era were very loud and very dark. Plus some of the best ones were incredibly crowded. To begin with, I could seldom get back far enough to get people into frame from head to foot and when I could, people would be constantly walking in front of me all the time. Then I bought a 24-mm lens and only had to be four or five feet away.

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.

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.

It's more about subtracting every single buck from the tourists that still flock there. Gentrification and the need for developers to maximize their profits from every square inch of the place means that there just aren't any scruffy little basement clubs left. Those scruffy little basement clubs were the areas lifeblood. Now, it's all penthouse flats and global brands. They destroyed the very thing that drew people there in the first place - it's superficial sleaziness.

To me, the counterculture was always what I grew up with the hippies in the late '60s. But, however you define it, it's really the excesses of youth and it's something that everyone goes through to some extent. Or if they don't, they should do.

That's one of the wonderful things about the whole process of photography - eye contact can be very revealing.

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.