My mother could look directly at a person and see them. Don't misunderstand me here. What I mean is, she could see the very essence of a person, just by looking at them. Not just the public face everybody learns to project, but the real, inner character. It was a dreadful affliction - seeing reality like that, naked and unadorned.

Something happened. She had to go and live in an asylum.

It's almost 20 years since my mother went away. I was just seven. It was a terrible loss to me and to my father. He couldn't explain it to me and he cried over the gaping void left in our lives almost as much as I did. We comforted each other as best we could. He told me that I was the image of my mother and looking more like her, when she was well, with every passing day. This seems extravagant flattery. She was so very beautiful: tall and slim, with bright auburn hair and flashing blue eyes, full of life and laughter. I don't laugh very often and I don't wear the pretty frocks I remember she wore. Perhaps I am like her, but I do my best not to attract unwanted attention. Now I'm strictly the jeans and tee-shirt sort and my hair is short and sensible.

At the age of about 12 or 13 I started to see reality too. But I was lucky. Quite lucky. Reality confined itself to reflections for me. I didn't have to look it straight in the face as I talked to people or greeted them in passing. Still ... . Have you ever noticed how many shiny, reflecting surfaces there are in the modern town? So, so many. I tried not to look for a long time. Most people looked little different to their outward appearance - perhaps more worried or frightened or angry. A few looked vile, monstrous. And they frightened me terribly. Later, I learned that it was better to be aware than to avoid knowing about these evil people.

A short while ago I was window shopping - looking for a big kitchen knife. There were a couple of likely candidates in this window display and as I was looking from one to the other I saw a man standing behind me. The expression on his face gave me a horrible jolt. It was mean, hungry, depraved. I cringed away from him then stepped aside and turned to face him, teeth and fists clenched - as if he'd already physically attacked me. He stepped back, apparently even more shocked than I was. But his face instantly relaxed, as if by reflex and he smiled kindly, like a normal, mild, gentle-man. I swivelled back to look at his reflection. It was ghastly. After that I couldn't finish my shopping. Instead I hurried home to ponder this alarming development, in safety. I didn't feel safe. Seeing reality can have that effect on you.

It was 6pm, time for the news. I poured myself a glass of wine and turned on the television. The national news finished with a weather forecast and I realised that I'd paid no attention to it at all. The awful face leering at me in the shop window had distracted me through the whole programme. So I made a particular effort to concentrate on the local news programme that followed. There had been another murder in my town. Very nasty, the police spokesman said; couldn't give details at this stage, but the lady had been mutilated - the MO was similar to the previous five cases within the last few months.

That focussed my thoughts marvellously - back on that odious face, seething with malicious intent. Intentions that involved me. I had no doubt of that. His deadly gaze had been fixed upon me. And he was a killer. He enjoyed killing. That was clearly written in his reflected features.

Reality can be ... is, inexplicably horrible.

There's no point driving yourself mad. I had another glass of wine and attempted to steer my thoughts in more cheerful directions. He didn't know where to find me and there was no reason to suppose I would ever see him again.

Next day, walking home from work, I stopped by that shop again, to buy my knife. I pondered at length, this time inside the shop and, finally selected a big sturdy machete-style chopper. As I stepped out of the shop door I saw the kind-looking man with the frightful reflection, window shopping again. He smiled benevolently at me. I didn't smile back but gave his face a searching look, endeavouring to discover the signs of corruption that I knew must be there, somewhere. This caused him to flinch slightly, but again, his congenial expression bounced back almost instantly. Then I turned to survey his reflection. Rotten! Foul! I hurried away.

Even though I tried to put it out of my thoughts in the following days, the horrible expression on his face, reflected in the shop window, constantly haunted me. I kept imagining him, creeping up behind me, diabolical features thrust forward and twisted into an eager, repulsive leer. The horror gripped me for so long, it was wearing me out, grinding me down and unbalancing my mind. Finally, I managed to persuade myself that it was irrational to allow this private hysteria of mine to grow.

During the next fortnight or so, I paid closer attention to the reflections. I became accustomed to seeing some bizarre projections of people's true natures and personalities. As ever, most of the people, most of the time, looked very like their reflections, but some few differed completely, body from soul, so that you would be unable to match reflection with owner in one of those identification parades.

One night, after visiting my mother, I sat in a bus shelter waiting for a bus and watching the dark window of the bus station opposite. Most of the people passing were young and drunk - and many were completely uninhibited. Some of the reflections in the window were quite shocking and others were hilarious. Primitive, drooling ape-men, some dressed in sharp suits, others in Hawaiian shirts, jeans or shorts, lurched along in small, wobbly groups. The drunker individuals became almost indistinguishable from their reflections, as the line between private intentions and public image dissolved in the alcoholic fug. Most of them didn't notice me, tucked away in the dimly lit corner of the shelter. But four or five, who were still capable of getting both their eyes to point in the same direction, did stumble over to say hello ... and a few less repeatable things besides. Lax face muscles toiled to gather uncooperative cheeks and jowls into friendly smiles but settled, in most cases, for lascivious leers. The fetid fumes of alcohol, cigarettes, sweat, vomit and after-shave wafted across my face enticingly - but I resisted the 'aphrodisiac' effects with considerable ease. And eventually these loud, friendly and unsteady gentlemen wobbled away, to find and pursue the lurid looking procession of Sheela-na-Gigs who staggered, strutted and cavorted down the road, all but assuming the classic pose. Perhaps I shouldn't have been so surprised at the reversion of the inebriate to our most primal instincts and behaviour. I made a mental note to cut down on my own alcohol consumption. Then I saw that man again.

He was following at some distance behind a particularly raucous crowd of the na-Gigs. My blood ran cold. He was unaware of me and making no effort to look kind and benevolent. His demeanour was sober and sly and purposeful. I looked at his reflection and gasped. It was demoniacal - resembling some awful stalking satyr. He heard my gasp and stopped. Turning his head slowly, he fixed me with a baleful stare. Coming to my senses, I pretended not to notice him, made a show of rifling my bag for a handkerchief and feigned a sneeze. After a few moments, satisfied that I was not, after all, observing him (or so I prayed), he resumed his pursuit. And I almost fainted from terror. If I had not been frozen to the spot by mind-numbing dread, I couldn't have forced myself to wait for the bus, but would have fled in blind panic through the dark and threatening streets.

When the bus eventually arrived, I was at least able to move again. My stomach was still churning however and I felt chilled to the marrow. I just wanted to put miles between myself and the fiend. Trying to re-establish my equilibrium, I told myself that the world must be full of terrible people. I just happened to notice one of them. So what? It's no big deal. Other people see him and don't know they should be afraid. Time to calm down now. Nearly home. But ....

But the fiend noticed me too. That was the problem, of course. I'd been noticed by a fiend. Again! As we turned the corner into my road, I looked towards the bus stop. There was a man, dressed in the same dark suit and jacket, same dark hair, same .... same man! He was leaning on the lamp post opposite my house. Found me. All those times when I imagined - felt - he was behind me, flashed through my mind.

I ran the last 50 yards to my house, fumbled the gate latch, dashed up the garden path, dropped and retrieved the front door key, before I managed to get through the door and slam it behind me. I felt faint. Cold and faint. Trembling. I knew somehow. I knew he would find me. That's what fiends do. That's why I was afraid. Because somehow, on some level, I knew. A bond had been forged the first time he saw me. That was the look I'd recognised in his eyes - the hell-light I'd seen in his hateful, reflected eyes. And that was the reason for my fear. Because I knew. And he knew!

My heart was almost leaping out of my chest. It was hard to get air into my lungs. The effort to keep my body from collapsing and my mind from drowning in an ocean of dread, forced me to engage in reason once more.

After a few minutes my mind slowed down and the panic subsided a little. I went upstairs to look out of the landing window. At first I could see nobody. But then I spotted him, lurking in the shadow of the bus shelter, observing my house. I suppressed the urge to vomit.

What should I do? What could I do? What could I say to the police, if I called for help? I can see he's a monster from his horrible reflection? No. They'd think me mad. At least I'd be safe, if they locked me up in an asylum. Wouldn't I? No. No. No!

I was too young to understand what was happening when they took my mother away. I missed her so terribly. She had been warm and loving, sang to me and told me stories, made me feel better when I hurt myself. One day she had been happy and playful, her pretty eyes smiling and kind - the next her face was like a blank wall. A little while later she was gone and she never came back. The facts came to me in fragments dropped by family and doctors. I had to fit the pieces together myself. My mother had fallen prey to some evil brute who had started by stalking her and threatening her and had finally attacked her. She survived, physically at least, by blind luck. The attack had been interrupted by a passing soldier, home on leave, who just happened to be taking a short cut across a field. It only now occurred to me that, in all likelihood, she was aware of the attacker before he even saw her. She would have seen the fiend, where anyone else could only have seen a man. She would have reacted with a clear display of fear, which he, in turn, would have found irresistible. At the moment of eye-contact between predator and victim, the link would have been forged, her fate sealed.

And now it was my turn.

Anger was blossoming and radiating out from the pit of my stomach. Lovely, useful, galvanising anger. At last. Helplessness could go and cower in a corner of its own choosing. I had no further use for it. There was only one person who could look after me. In order to do so, I would need to stop quaking and start thinking. I took off my coat and put the kettle on.

Sipping my tea, I returned to the landing window to look for him. He'd left. Or he was hiding.

How does a maniac think? I tried to put myself in his mind. What did he want? Power? Yes. That must be the main motivation. To generate fear? That had to be a significant part of it. So, was he likely to strike tonight? In my home? It was his best chance. That look in his eyes ... it was ... what was it? Imminent! He looked hungry - starved of that longed for thing.

I should be prepared. It was me against him.

Formulating my plan, I became completely calm. And once the plan was devised, I felt entirely cool and unafraid. By midnight I'd been through each room several times so that I knew the location of every object to within a millimetre - just in case there was a pursuit. I wouldn't be tripping over things and impaling myself. He might, if there was a chase. I drew all the curtains to exclude any light and reflections. Then I removed the fuses. If he wanted light, he'd better bring a torch. Much good it would do him!

This was how a maniac would behave. It was shockingly easy for me to assume the role. I felt confident as I took my machete and wet stone upstairs to the empty spare room. It was a long wait, methodically, deliberately sharpening the blade. 3.30am I heard the stealthy sounds of the back door being forced. I got up from my hard, uncomfortable chair in the corner and moved silently to the centre of the room. There I squatted on my haunches, the point of my now wickedly keen blade lightly pressed to the floor. I suppressed a giggle. He was going to be so surprised! Such a shame that I wouldn't be able to see his face. This was more fun than I could ever have imagined. But hard, so hard not to laugh and give away my location and spoil the game.

I rocked gently back and forth, eagerly willing him to stop bumbling and rustling around downstairs and come up to where he would find his big surprise.

It seemed to take forever for him to check every room. The light of a torch swept by the bottom of the door and he slowly turned the handle. I prepared to spring as the door opened the merest crack. He'd hidden his torch beam. Then he boldly swung the door wide and swept the beam across the room. As it shone on my face I leapt at him with a triumphant shriek and brought the machete up in an arc under his jaw, which cut off his own scream of fright with shocking suddenness. The torch skittered across the floor and came to rest under the window. The man crashed where he stood, gurgling and spluttering. I retrieved the torch and shone it in his face. He just looked like a pathetic dying man.

I smiled at him and told him that all the pleasure had, in the end, been mine.

As a final thought, to satisfy my curiosity before his life expired entirely, I took a mirror down from the wall and placed it before him, so I could see if he still appeared a monster. He looked at his own reflection with an expression of terror and when I looked, for the first time, I saw that his reflection matched his physical appearance. I, on the other hand, looked like the spawn of hell.