"We are most honoured to welcome an ex-pupil of the School – a young man who has achieved great things in the service of the Empire, and stands as an example for all our present pupils to follow!"

Mr Colyngbourne beams around the assembly, and leads the staff and prefects in a round of applause. Our honoured guest smiles deprecatingly. He's a handsome chap, is Philip Hanley. Inspector Philip Hanley, whose rise in the ranks of the tax inspectorate has already been meteoric. He's the charmer who can be depended on to squeeze the last penny from a poverty-stricken smallholder and turn a blind eye to the conglomerate boss evading tax revenue on billions - in return for a slice of the profits, of course.

He doesn't see me, of course. Now that I'm a Sixth-Former and the very devil of a fellow, I can choose where to sit. And I usually sit in the shadows between the pillar and the wall at the far end of the hall, where I can see everyone and watch everything.

It's part of the lead-up to the close for the summer holidays to have inspiring guests. Presumably it's felt that they provide concrete proof of the heights that departing pupils can aspire to if they kiss the right arses.

I somehow thought it would be worse than it is, seeing him again. But eleven years have passed, and hidden in my chrysalis things have changed. I don't see him as twice my weight now. I don't see him as stronger than me. I see him as something quite, quite different.

My transformation isn't complete yet. I'm still a work in progress. But I will be complete one day, and if my carefully laid plans come to fruition, today will be the first of six steps towards it.

Back in the day, when I first conceived of myself of a creature in a chrysalis, I had the idea of being some kind of jawed beetle when I emerged – there were some fabulous ones pinned on boards around the biology class. These days, however, my ideas have gone up a few notches. I rather like the idea of being that interesting creature that burst out of somebody's belly in an old film we watched the other day. Something about the dentistry just appealed to me...

I'd imagine that if Mr Fletcher was still here I'd at least have been given the courtesy of being warned in advance – perhaps even given the option of absenting myself on some kind excuse or other. As it is, I learned of it because I hacked into the school's mainframe years ago, and there isn't a damn thing that goes on in here that I don't know about. I eavesdrop on conversations, I copy confidential e-mails. I'm blackmailing half of the staff and most of the governors, and one thing I arranged for was for him to be transferred. Into a nice, cosy, well-paid job where his stupid niceness won't be so utterly wasted, and where he'll be safe from the wrath that is to come.

Colyngbourne, the fool, hasn't a clue. He's sitting on a sunlit leaf while in the shadows all around him the webs are closing in. Miss Ratcliff sits beside him, her smile complacent, her hair immaculate. She's on a nice little earner these days, should get a nice pension when she retires. Or she would do, if she lived long enough.

Which she won't.

Hanley's the guest of honour. He gets to distribute the prizes, hand out the certificates. Strangely enough, mine got lost in transmission yesterday, so I won't be called up to the podium for him to shake my hand and congratulate me on my outstanding academic achievements. Madame Delacroix the school secretary handed the prints to me without a word of protest; I can still remember the way her throat muscles moved beneath my fingers. While I had the chance I put my free hand down her bra and had a bit of fun, and if I hadn't been in a bit of a hurry I'd have pushed my hand up her skirt and had a feel there too.

Did I mention I lost my virginity quite a while ago? It was such fun I've repeated it on quite a few girls since. They must have enjoyed it, for all the whimpering and crying they did. None of them reported me, anyway.

Madame Delacroix sleeps with her door padlocked. Can't imagine why she should do such a thing, but I saw the gleam of it when I climbed the ivy up to her window last night. Unfortunately for me, the window was locked too. Tightly, for all that it was a hot night, and moonless. She wasn't asleep either. When I tapped lightly on the glass her head turned on the pillow, much too fast for someone who'd been in the land of Nod. I ran my tongue up the glass, slowly and lusciously, to show her what she was missing.

(You're wondering about Christopher, aren't you? He disappeared soon after my 'medical emergency', and his missal was gone out of its hiding place too. I don't know whether it was found and reported or his dad got taken by the BII. Once that happens the whole family gets scooped up like tiddlers in a net, so that would have been the end of Christopher.)

So. Prize-giving. A dead bore at the best of times. The certificates mean fuck-all to me, the results are all stored away on the Education Authority's main database and sent out to the universities. I already know where I'm headed, I've more than exceeded their admission criteria and my route to the Royal Naval College is mapped out. My scores in shooting competitions would qualify me for the Olympic team if I could be arsed, but I've got my gaze on far more rewarding targets. One of the Empire's sharpshooters can rise and rise. I'll start off with a lieutenancy on a warship, and then the killing will really start. I'll have the latest weapons handed to me, with carte blanche to fire. I'll make that ship the terror of the seas, and the seas will only be the start of the terror.

And then, when I have power, Phase 2 of the plan can come into effect. Slowly. Stealthily. Surely.

I have patience.

This patience is tested during the day. There's prize-giving, and speeches, and a tour of the school ('It's so much smaller than I remember!'), and blessed peace for a few hours while he bores the staffroom to death, and then dinner where he's the guest of honour, and whatever, whatever. But I'm patient. I've been waiting for eleven years, and I can wait a little longer.

There's a paring of a moon hanging over the trees when I slip silently into the roofspace of the senior girls' dormitory.

I know my way around perfectly well by now. The rooms are air conditioned, and each has a vent in the ceiling. Luckily for me, and very unluckily for some of the girls, these are modern and easy to unscrew and lift – for maintenance, officially, but it comes in exceptionally useful for other purposes, mostly mine.

I've already selected my unwitting co-conspirator. Mithra hasn't the courage of a rabbit even in broad daylight, and she just collapses into a heap of whimpering rags when I land lightly on the floor. Needless to say, she and I are very shortly horizontal, and while I pleasurably ensure that there's plenty of my DNA in place if I should require proof to be produced for my alibi, I whisper in her ear exactly what will happen to her if by any chance she omits to mention the next day that I spent the entire night between her legs ... at her express invitation.

Having taken care of that little matter, I leave her to decide to be a sensible girl, and exit by the window. My gloves will ensure that I leave no fingerprints, and my soft shoes with excellent grip make no sound on the wall that connects this building to the staff annex.

I'm not afraid; on the contrary, I'm keyed up to a pitch of excitement I can't ever remember experiencing before. The explosive pleasure of ejaculating into Mithra seems merely like the overture to a symphony.

There's a skylight at either end of the annex. A screwdriver quietly finds the catch, which has been left not quite secure, though you wouldn't know it from below.

Everything inside is dark and still. I slip silently through the aperture, careful not to let my skin touch at any point, and let myself drop. There are advantages in being small and slim, and clad from head to foot as I am in black clothing, I simply become a shadow among the other shadows.

The accommodation database on the school's computer has told me exactly where I need to go. A visit to the secretary's office some months ago provided me with a copy of the master-card that will open any door in the building, so there's no need for force, no need for anything that will leave the faintest clue to how or who; and my access to the database makes it simplicity itself for me to erase any record of the door being opened.

The door lock flashes green, covered by my hand, and I'm in. A previous visit ensured that the handle moves without a sound, and I'm in the guest suite and within reaching distance of the first step in my transformation.

The wine was flowing freely at the High Table tonight, in honour of such an exalted guest. It's almost a pity that his senses won't be at their brightest and best so he can experience his last few minutes of life to the full, but that's no reason for me to waste all the effort I've put in.

In a mirror on the wall I catch a momentary sight of my own reflection. I like it. Its smile is a row of bared teeth.

Still, Mithra will be waiting eagerly for the second and third courses, and a gentleman never disappoints a lady. She really does have the most beautiful body, supple and slender, with small, perfect breasts and an absolute peach of a bum.

I step to the bed, slipping from my pocket a knife I made in metalwork class without anyone seeing. It's not beautiful, but it's superbly functional. The blade can cut lengthwise slices from a human hair without bending it.

The heat means that Hanley's sleeping under nothing more than a sheet. His face is innocent with sleep. Ruined little people mean nothing to him, the happy bosses fill his offshore accounts and that's what matters.

Not that I'm a saint, by any measure. I don't give a toss about the little people either. I was one once, and look how that turned out.

A saint wouldn't run his hand lightly across a man's mouth and then clamp it shut. Wouldn't give his victim just time to open bulging eyes that meet mine in appalled recognition before driving the blade into the base of his belly, ripping it upward.

My hand smothers the best attempt he can make at a scream. The knife plunges and rips, again and again, while he thrashes and gurgles and sobs, pawing ineffectually at my imprisoning arm; the skin-tight fabric I'm wearing ensures he can get no grip on it or me. He's a fully-grown adult and I'm not quite, but he's soft and already flabby with too many good dinners, living on the fat of the land, while I spend every spare minute in the well-equipped sixth form gymnasium and I don't waste a single second of them. I'm as lean as whipcord and every hard muscle in my body is in play against him. He was dead as soon as I got my hands on him.

It doesn't take half as long as I'd hoped it would before he finally falls still, his jaw dropping open, his bitten tongue dangling from his mouth and his eyes still staring in sightless, horrified astonishment as I cautiously ease my grip. The shock of the initial attack was too strong, my enthusiasm too great; obviously I can't dawdle, but my technique clearly requires more finesse before the next time. It's a learning curve, and next time I'll take more care not to get carried away by my excitement.

As I withdraw the knife, blood trickles from the blade over my hand. Automatically I lick it, and the taste is that of victory, vindication. I lick up the rest, loving the feeling of it in my mouth as the assurance that the days of my helplessness are over.

I slip from the room, closing the door soundlessly. Ten minutes later I'm in the boiler room and everything I've been wearing is in the incinerator, already roaring to heat the water for the morning showers. Without haste I pull on the spare set of clothes I secreted behind it. No fibre on my clothing will match any from the scene of the crime, even if my alibi should be questioned.

Ah. My alibi. I smile into the night, stretching luxuriously. Sweet little Mithra. I just know she's aching for me to join her again and resume where we left off. And if by any chance she isn't ... well, as I found out long ago, what you want doesn't matter when you're the prey rather than the predator. And now, I am the predator.

And the night belongs to me.