'I enjoyed the daft ritual, the euphoria. We were all on it'

In the 12 years after leaving university I made such an incremental transition from stern critic of class A drug abuse to regular cocaine user that I barely noticed I had switched sides.

At 20 I hadn't even had a puff on a cigarette. But by my second year at university I was sharing a student house where we experimented with dope, magic mushrooms and LSD. Cocaine remained the preserve of the jeunesse dorée who ruled the university's social roost. I despised the joyless excess. And when I graduated and started working for a small publishing company in the West End it was easy to transfer my contempt for the trust-fund cokeheads to the media variety.

And then I too acquired a boyfriend with a drug habit. One evening he persuaded me to try a line. To my surprise I enjoyed both the daft ritual and the cocaine - all the euphoric benefits of a glass of champagne without getting drunk. Nor did it make me feel, as I had feared, any loss of control or compulsion to talk nonsense. Some people are at their most fluent and amusing when on cocaine. The arsehole factor tends to predominate among users who are already objectionable and scavengers whose habit is so entrenched they would do anything for a line.

You can't tell a cocaine user just by looking: you can only pick out the obvious ones like advertising executives and rock stars. I have taken coke with doctors, housewives, art dealers, financiers, seriousauthors and even with a couple of relatives. Many of the users I know are over 40, and several are over 60.

In my twenties I was a small-time party coke user and only took the drug if a trusted friend offered it. Whole years went by without glimpsing a line. When I hit my thirties my career progressed and my income doubled. As Robin Williams said: "Cocaine is God's way of telling you you're making too much money." Everyone in the world I moved in seemed to be taking the stuff. Nor were they all the cretins of legend. Some of the most interesting and stimulating people I came across were users: there's always been a link between creative imagination and vice. Like the executive who doesn't play golf, the creative who doesn't take coke may feel excluded from the bohemian subculture. Playing Russian roulette with your looks, reputation and talent is one of life's greatest thrills when you feel so young, powerful and immortal.

By the time I was 33, I had taken coke in a Soho club's loos for the first time (laughing with the ghost of my former self at the grim cliché I was becoming) and made the fateful step of acquiring a dealer. There were months when I didn't take any, and I used the fact that I knew many people who took far more cocaine than me to excuse my own consumption as minimal. I was as likely to use the drug to keep abreast of my increasingly heavy work schedule as socially. Cocaine seemed to give me an extra day in the week. But I knew that regular coke use took a toll that was hard to quantify.

One of the many addictive qualities of cocaine is that when you're spiralling out of control it seems to put you right on the edge of the trauma. It makes you feel emotional pain as a burst of addictive excitement. But it is also like putting your body into an ever-increasing overdraft, where eventually there's no way you can repay all that borrowed energy. And I became paranoid that a number of colleagues and acquaintances might be whispering about my habit. Did they perceive me as being the kind of flakey media cokehead I most despised? I was reluctant to admit to any degree of dependency. Not even my current partner, a man who finds all drug use "unbelievably stupid", knew the extent of my habit.

I spent most of the next three years either having babies or rearing them. But my calm, domesticated life was making me feel a little stir-crazy. The long-suppressed itch only needed the tiniest scratch, butI knew with every fibre of my being how insane it was to risk my partner's and children's happiness.

I thought of the four people I had known whose untimely deaths were due to heavy drug use. I thought about the grim blood toll paid en route for every assignment of coke that reaches these shores. And I stopped taking cocaine. It wasn't very rock'n'roll - but then neither is a spell in a cardiac unit.