Wanda answered the door, smiling, and pointed upstairs with her cigarette. Someone had given her a carton of long Marlboro Lights and before lighting one she would break a bit off the end and mutter 'Hooker cigarettes'.

I liked Wanda. Sharp. Funny. Long dark hair, ex-model. Fabulous smile. Slinky black dress and loafers, epitomising ironic glamour. But something was wrong. Upstairs she waved her cigarette and talked in quirky sentences that I could not quite follow. What was she saying about the price of the curtains? 'What do you think?' she asked, as her decor story fell to pieces.

I thought: 'This person has taken some fast drugs and lost her sense of humour, and I think that was my favourite part of her, so now what are we going to do?' I tried to follow her mind as it danced on the horizon. 'Are 3.2you . . . all right?' I asked, like some Valley Girl in a TV sitcom. Yes, she was, sure.

Unconvinced, I told her about a strange vision I once had. She failed the empathy test, trying too hard. Ten stilted minutes later I asked outright: 'Wanda, have you taken cocaine?'

She remained unstartled. No. A small muscle twitched in her jaw, under her mask of Frosted Beauty. I ticked it off the checklist. But yesterday, she said, she had done three lines. Just as a little celebration. Or was it to help her through a tired spell at work? Both, maybe.

OK. I could contain my contempt for cocaine, the bad person's drug, begetter of word salad, arrogance, narcissism, delusion, impotence and, eventually, psychotic rage. After all, that was yesterday, right?

Of course she had not taken cocaine tonight. This was our first proper date. We were going to dinner at a designer restaurant, all scarlet walls and purple banquettes and . . . 'Oh, isn't that Seal over in the corner?' Yes, I think you're right. He comes here all the time.

We dined with her friends Oscar and Anne, and some others. Sort of. Wanda did not want to eat. So I smiled while she fidgeted and pawed me and drank lots of wine and draped her long, elegant legs over mine and went to visit friends on other tables. When she blew smoke across my tuna steak I saw only the carefree spirit of Voluptas, goddess of sensual pleasure, in her actions. Naturally, I picked up the bill; pounds 20 each. 'Could we just go to Bert's for one drink?' she pleaded.

Bert's? Miles away. Harsh. Sweaty. Cramped. Bar full of drunks, toilets full of zombies with numb noses. God knows how the staff, who are actually quite pleasant, put up with it.

'To score coke?' I sneered. Yes, but not for her: for Oscar and Anne, who had just flown in to town on holiday and wanted to party. You know.

At Bert's they drank a lot and worked the crowd. I asked around, too. I wanted them to score so we could all leave, quickly. Too late, said the dealers. All gone. Eventually, Wanda shouted into my ear, 'Hey, we got something. Here's yours.' She placed three-quarters of a white pill in my right palm. 'Ecstasy? After dinner? Can't we wait for a better time?' But she and the others had taken theirs already. Oh, what the hell. I washed the chemical crumbs down with her vodka.

I was happy when our cab arrived. But where to? 'Dunn's,' said Oscar. I looked at Wanda and shook my head in disbelief. She shrugged: it was their idea. Dunn's] Hollywood nightlife with a hint of the Old Kent Road. Air-conditioning set to deep-chill factor. Dry ice on the dance floor. Dark, glossy, expensive bars; uniformed staff; George Michael records; south London dealers in Versace grunting at damaged dollies in Alaa. A coke joint.

In one flowing movement the doors opened and we swept past bouncers who greeted Wanda by name, onwards, upwards, to the far end of the top bar, where, without a word or a glance backwards, she and Oscar peeled off and disappeared into a back room, while Anne ducked into the Ladies.

I stood wondering about Wanda, while two geezers scowled at my Birkenstocks. I hoped I was wrong. Perhaps she was just doing the introductions. Anyway, I could not go home. My key was at her house, in Kensington. Oscar emerged and joined me. 'Did Wanda get some coke?' I enquired, trying to sound upbeat. 'Oh, yeah,' nodded Oscar, eyes wide, slurping his vodka.

A night at Dunn's with three drunken cokeheads is not my idea of fun. I went downstairs to phone a friend who might put me up. No answer. When Wanda emerged and insisted she had not been scoring coke, I turned on my heel and stormed off, while she ran after me squealing: 'Wait] Wait]'

I stamped off into the night, my name echoing after me. In Soho I sat outside a bar and tried to think. Where should I go? It was 3.30am, and I felt sad and angry and very tired. Then a warm sensation uncoiled in my stomach, seeping down into my groin, up along my spine and out into my limbs. Of course. The Ecstasy had finally kicked in. I found myself smiling at the absurdity of it all.