It was summer, the middle of a hot spell. My fair, my lovely Ruth was still transporting me to new levels of joy and passion; our delightful Jamie, chubby cheeked and earnest Jamie, was continuing his education and proving a most able and willing student. The constant blue skies formed an airy backdrop for a gentle, easy lifestyle; in the shimmering sunlight people cast aside their worries and insecurities. We stepped out in loose, casual clothing; we flung our windows open, inviting the sunshine into our homes and our lives; people smiled at strangers and lingered to talk to friends; a carefree, relaxed atmosphere descended, enveloping us in its warmth. This was the good life.

I lived in a semi detached house in an ordinary residential area. Nothing special, but it was mine, and I loved it. I had good neighbours on my side of the street. Margaret, next door to me, was an elderly widow, for whom I was like a surrogate daughter. She looked after me, fussing diplomatically, shaking her head almost imperceptibly at my lack of housekeeping skills, or late nights, or bad dress sense. She disapproved of my lifestyle, but in an indulgent way, realising that I was a product of my times. I loved her for that tolerance.

Directly opposite me was an imposing Georgian terrace, long since fallen from the grandeur of its heyday, and now transformed into a series of flats and bedsits. An everchanging roster of curious individuals, students in the main, plus some people on Benefit, inhabited them, infusing the neighbourhood with colour and vivacity and a certain louche charm. There was constant activity and bustle, people coming and going at all hours, hanging from windows and balconies, conducting long-range, high decibel conversations. The elegant steps, once graced by nervous gentlemen paying their respects to young ladies, reverberated to the rhythms of a dozen ghetto blasters and played home to countless impromptu alfresco parties. It was an anarchic place, but not in an intimidating way; there was a self-confident arrogance about it, the residents comfortable with their way of life and outlook, and careless of what others thought of them. Margaret, of course, hated it, thinking it lowered the tone of the neighbourhood, but I liked it: it added colour, variety and interest to what was otherwise a drab and nondescript area.

Over the couple of weeks of the heatwave I had grown accustomed to lounging about the house in a tee shirt and shorts, or even just tee shirt and panties. It was too hot for anything else, and besides the feel of the slight breezes on my bare thighs was mildly stimulating. The windows were permanently wide open and what wind there was would tug gently at the curtains, occasionally billowing them into a flurry of activity. This would attract my attention briefly from the book I was reading, sat on the settee. It was then I began to notice that there was movement behind a net curtain in the flat directly opposite mine. The first few times, I didn't really take any notice. There was nothing unusual about curtains moving about: indeed, it was the movement of my own that was attracting my attention in the first place. But gradually I became suspicious that there always seemed to be some shaking of the net curtains when I looked up.

I experimented with looking up suddenly, and generally the curtains would twitch briefly. Then I tried to see out of the corner of my eye what was happening without it being obvious I was looking. There would be nothing until I made a show of looking up again, when I would see a familiar flick of the net. I was becoming certain: somebody was behind that curtain, watching me. At first I didn't really take it seriously, not believing it. I got up to the window and stood in front of it, trying to stare in, but couldn't see anything. For a couple of days I thought no more of it.

I was reading the last few pages of a novel, thinking about what I would prepare for lunch, when a gust of wind blew my curtains inwards. I looked up and saw, yet again, a flicker in the curtain opposite. But this time the sun was shining directly onto it, basking it in forward lighting. And there was a human shape standing behind the net. It was only there for an instant before disappearing into the hidden depths of the room, but it was long enough for me to see. Now I knew. I was being watched.

A cold wave of trepidation washed over me, filling me with incomprehending dread. My heart literally stopped for an instant, then leapt in my chest and started to pound. My mouth went dry and acidic, my arms came out in goosebumps. I was frozen to the spot, frightened to move from the settee. I daren't look up again, but couldn't decide which concerned me most: the thought of seeing the person again or there being nothing there but the greying curtain. Pretending to read my book, I tried to glance upwards, but by now the sun had moved and the room behind the curtain had retreated once more into bland anonymity.

Suddenly aware that I was dressed only in tee shirt and panties, I pulled myself out of my fear induced indolence and fled to my bedroom. Shakily, I pulled on some jeans and headed for the kitchen to make lunch. I concocted a cheese salad sandwich and ate it standing at the sink. Somehow, I couldn't bring myself to go back into that living room. Not just yet. I tried to think over the last few weeks, piecing together the little fragments of evidence that I had not considered, or wanted to consider. Then, my heart pulsing into anxiety once more, I tried to remember if I had done anything which might have been overseen: there were a few occasions when I had scurried out of the shower naked and into the living room in search of a hairbrush. Oh God, could he - I presumed it was a he - have seen that? Ruth had been round a few times, but that had always been evenings, by which times I had drawn the curtains. And that was just as well, I thought, grinning, happy memories pushing out for a moment the grim immediate concerns. Not for long, though, as the thought of someone spying on me preyed on my consciousness. I felt helpless, almost a victim, even getting tearful at one stage.

Over the next couple of days my fear gave way to annoyance and downright anger that someone should be invading my privacy in this way. How dare he, I thought. The bloody pervert! I was damned if I was going to close my curtains during the day, or wear hot, sticky clothes just because some loser was ogling me from over the road. I harboured notions of going over and confronting him, working through dialogues in my head, imagining conversations in which I berated him for his anti-social behaviour, before coming to my senses and realising any such course of action could be highly dangerous.

Gradually, though, the anger subsided, and an element of curiosity took over. I began to wonder who it might be. Was it some old man, sad and lonely, looking for a bit of titillation? Or some shy, young stud? I especially liked that one, of course. Or a fat, balding, middle aged man, more likely? Or even a woman, I thought. I concocted all sorts of scenarios, considered people of every description, taking pleasure in imagining the grossest, or the most attractive, or the least likely, or the best fun. I started to enjoy my fantasies, sitting on my settee looking at the curtains over the road. I found myself almost willing them to twitch again, and reproached myself for my stupidity. Rapist, I told myself sternly, imagine it's a rapist. Then you won't think it's such fun.

No matter how I tried, though, I couldn't stop thinking about who it might be and, deep inside me, I knew I was curious to find out. I found myself thinking about it more and more, and was appalled to realise that, even when I had no cause to, I was popping into the living room to catch a glimpse of the window opposite, looking for movement. It was frustrating that since that day when I saw the shadow I had seen no sign of my phantom observer at all. He had clearly realised he had been seen and was frightened off. I tried to tell myself that was just as well, but deep down I was disappointed that this fantasy had been nipped in the bud before it could even begin properly.

As the days went by, with no sign of my observer, I began to lose interest. The heatwave was still with us, but had developed a sultry, airless aspect. Where once was lightness and freshness there was now a stultifying stasis; people and events were in slow motion, torpid and listless. Everything was an effort, nothing seemed much fun. I settled back into my routine of reading on the settee, because I couldn't summon up the energy to do anything else.

I don't know what made me look up, that Friday afternoon. There was no air to blow the curtain, no noise to attract my attention, and I was reaching an engrossing part of my story. But, unconsciously, I looked up. And there it was, a twitch behind the net curtain. He was there again. I held my gaze, continuing to stare at the window opposite, sure that he was still there, lurking in the recesses of the room. I was certain that at that moment I was being watched, and was aware of butterflies in my stomach and a surge of excitement passing through me. Behind that dirty, anonymous, net curtain I was sure someone was standing, looking. The thought was turning me on. My nipples were standing hard, jutting through my tee shirt; my breath was shallow and fast; the first stirrings of interest were aroused, giving rise to that sensual anticipation which you can't work out whether you're feeling in your mind, your chest or your pussy. Minutes went by and there was no further sign of activity; there was no point hiding it now, I was seriously frustrated that my fantasy situation had been resurrected only to disappear again almost instantly. Just when I was beginning to forget it, up it popped to remind me.

It was no use. I had to find out who lived there, who was watching me. The obvious answer was to check the electoral register, although the residents of the terrace were generally not very permanent, so this was unlikely to be entirely reliable. To do that I would need to know the number of the flat.

To that end I drank a bottle of wine one evening, for Dutch courage, and late on sneaked out of the house and over the road to the terrace. I rushed up the grand steps and pushed open the door of the communal entrance. It was huge and took some effort to shift. Once it gave way I was faced with a stone corridor, dimly lit by a fading 60 watt bulb hanging shadeless from the ceiling about ten yards in front of me. Shrouded in darkness beyond that, I could vaguely discern a set of stone steps curling round and upwards, bounded by a wrought iron banister. I had calculated that I needed the second floor. With an intake of breath, I made for the bottom of the stairs and gripped the banister rail. It was cold in the hallway and I could see my breath before me: it seemed to emphasise my fear, becoming a physical manifestation of it. "Onwards and upwards," I thought, the cliche lightening my mood. Noiselessly in my rubber soled trainers, I slipped up the stairs to the first floor and then on to the second. On the landing I was confused to see three doors: I was only expecting two, one to the left and one to the right. Calculating that the one I needed was to the left I turned towards it, but just as I was about to check the number I heard the latch turn and a vertical beam of light appeared all down the side of the door as it began to swing open.

Panic stricken, I turned, instinctively heading for the nearest escape, which was up the next flight of stairs. Behind me, the door was opened and I could hear someone emerging. I hadn't made it far enough and the person would undoubtedly see me climbing the stairs. But, I calculated, it would be too dark for him to make out who it was. If I could act naturally, with luck, he would think I was just somebody who lived in the upstairs flats and think no more about it. Trying to hide or racing away as fast as I could would only make him curious.

"Oh wait for me, what's the hurry," I yelled, trying to create the impression that I was part of a group climbing the stairs. Consciously trying not to rush, I continued up the stairs, too scared to look back, but listening for any sign that he was following me. I could hear keys rattling, then the door slammed and the key turned in the lock. By now I was on the third floor and leaned over the banister slightly. There was no sign of him coming up. I heard someone whistling and footsteps going down the stairs, down one flight, then another; echoing, ever fainter, they went along the hallway and the front door creaked open; and he was gone. Aware suddenly that I hadn't breathed for the last minute, I let out a huge sigh and sat on the top step, my legs shaking, my heart pounding. God, girl, I thought.

I waited for a couple of minutes, unconvinced that my trembling legs could take my weight, but afraid the whole time that someone might come out of the third floor flats and ask what I was doing sitting on their landing. Judging it was safe to leave, I trotted down to the second floor and stopped in front of my observer's door. Number 27a. Armed with the information I had come for, I rushed back home and flopped onto the settee, exhausted but exhilarated, in sore need of some more liquid refreshment.

I did my detective work the next day. From the electoral register at the library I found a name, and from the telephone directory a phone number for 27a. I didn't know if it was still the same person living there, though, but on my way home I spotted the postman doing his late round. A couple of minutes flirting and fluttering my eyelashes at him and I had the confirmation I required. One person lived in 27a, Thomas Moore: now I knew something about my observer. Somehow, this made the situation less creepy, more manageable. He was no longer an invisible, ethereal foe, but flesh and blood, an ordinary person with an ordinary name. I knew more about him than he realised, and the balance started to shift. Buoyed by this, I planned my campaign.