Heart Searching: My date with a serial bastard: Sexy, attentive, honest: he seemed too good to be true - and he was, writes Sara Silver

Intelligent, educated, creative, tall, slim, sexy, stunning, emotionally literate, open, honest, caring, underemployed, solvent, sociable, affectionate, uninhibited, adventurous, interested midnight man, under 37, seeks equal woman for commitment.

His lonely hearts advertisement jumped out of the columns of dreary self-acclamations. As one friend said, he was either an arrogant sod or a truly unusual guy. I'd never met a man I could describe as honest, emotionally articulate, and truly egalitarian. Well why not suspend disbelief and keep an open mind?

I sat in the suitably casual but stylish Cafe Delancey, apprehensively eyeing the unaccompanied men coming through the door. A slim man swathed in black, long blond hair scraped into a pony- tail, wandered in. His confident gait as he walked towards me told me he was mine for the evening.

What was immediately noticeable about his manner was an unusual quality of interested engagement. His seductive air of total attentiveness was confirmed by sympathetic squeezes of my hand as we discussed the less pleasant details of personal biographies.

After an obligatory but cursory survey of relationships, we went on to talk about social issues. His discussion about the inner-city environment was followed by the disarming non sequitur: 'I'm just thinking how much I'd like to kiss you.' After more wine and a shared chocolate mousse, he put his arm around me to walk me to the bus-stop.

Thinking about our first meeting, I decided that perhaps he was indeed a rather special person, capable of relating with both passion and integrity. Perhaps it was also time to let down those defences and stop being so cautious. Most men were not like my ex, who told lies whenever expedient and became aggressive as a result of his conflicts over an increasing intimacy. So when we spoke the next evening, I invited Simon over for a drink.

I hadn't made love for more than a year, and I revelled in his warmth and playfulness. He held me in his arms the whole night - an unexpected pleasure. I was happy and relaxed over the weekend, I felt nurtured and was confident I would see him when he was less busy canvassing for the local council elections. My sister asked what arrangements we had made to meet again, but I was so certain we had already embarked on an intimate relationship that I was sure it would be soon. Yet three days had gone by; I began to wonder why he hadn't called. It hadn't crossed my mind I might never see him again.

Next morning, I telephoned to hear that the arrangements he'd made to meet a few other Time Out respondents over the weekend hadn't materialised and he was still pursuing them. I suggested he might have let me know what was going on, since we'd not merely met and talked but slept together.

I was beginning to realise this was irrelevant to him, that I'd been seduced by the ad perhaps even more than the man. I asked whether he was still deciding with whom he wanted a relationship, and when he said yes and that he thought he might give me a ring in a week or so, I asked whether I had anything to do with the decision, and what had happened to his notion of equality.

It was all empty rhetoric and with the turn the conversation was taking, Simon clearly couldn't wait to get off the phone. His solicitous manner had evaporated, leaving no sign of emotional literacy, and it seemed his own needs were the only ones he cared about. Still, no harm done, I decided. A salutary lesson of the power of one's own fantasies.

I contemplated sending in a similar ad myself, since I'd found his so attractive. Instead of the usual strategy used by women to outline what they wanted rather than describe their own qualities, why not use the more 'masculine' approach I had responded to - even if its designer had not proved very honest.

Some weeks later I was idly scanning the Time Out columns when I was astonished to see a virtually identical ad had already been placed by a woman. Convinced she must have met Simon and have a similar story to tell, I sent her a card.

Meeting Rosa in a wine bar brought a shock of recognition. We sat across the table, both part European, with brown eyes and shoulder-length hair. We quickly established that Simon's seduction strategies were virtually identical. She was convinced that his attentiveness meant their mutual attraction was special, and slept with him that night. We worked out Simon had called her the same day he left my house, and that there were others, although we didn't know how many. The apparent dialogue, full of negotiable possibilities, we thought we'd shared with this man emerged as two disparate monologues.

They slept together over the next three weekends. 'I would have married him if he'd asked me,' Rosa told me. He would bring commitment and children into the conversation, while at other times telling her about his jaunts to S&M clubs and other ads he'd responded to for group sex sessions. The penny dropped when he told her his supposedly ex-girlfriend was back on the scene and he was not interested in a monogamous relationship.

One night the following week, an old friend came round for a drink who turned out not only to know Simon, but another two women who had slept with him after an earlier ad he'd placed. And these were only the women I had, by chance, come to know about.

I was in the increasingly uncomfortable position of knowing rather too much about this man's behaviour, while I could only speculate on his motivation. He appeared to be so successful in manipulating women's desire for commitment in his search for sexual pleasure that I was beginning to wonder whether London was populated by his discarded partners. Having gone through the current batch of Time Out replies, I suspected he was about ready to put another ad in.

To answer a lonely hearts ad is a leap into the unknown. While you realise there may be a psychopath lurking out there, you have to take someone's self-representation on trust. Presenting himself in his ad as an honest and caring man who was both single and looking for commitment didn't square with Simon's compulsive sexual behaviour. Why are so many women taken in by his veneer of emotional engagement and attentiveness?

I wished there was an equivalent of the Advertising Standards Authority to complain to if the advertised description did not fit. From my own experience, Simon's ad could be more honestly written: 'Intelligent, educated, seductive, sexually adventurous, uninhibited, self-centred, dishonest opportunist with fear of commitment, seeks gullible woman tolerant of rampant promiscuity.'

I still haven't found that elusive egalitarian.