Back in the technology lab, the only problem remaining – apart from, that is, whether this will work or not – is the code that will be left on Pye’s supercomputer.

If I leave evidence of time travel in 1984, the risk is that someone will find it and piece it together. The results of that could be catastrophic.

A self-destruct program would be perfect: I run the supercomputer along with the self-destruct program: it gets me home and then wipes the discs. Only I don’t know how to write such a program. Wouldn’t know where to start, in fact.

The only other option I can think of, then, is setting the whole lot on fire.

In the janitor’s store are several tins of creosote, the brown wood preserver used on fences, and some steel wool.

Twenty minutes later, and everything is rigged up: Pye’s supercomputer is connected with electrical cable, via the black box, to two zinc buckets arranged to touch one another on the floor, and more electric cables, with wires exposed at the ends, form the improvised hand grips. The shiny black box is in one of the buckets, connected with wire to both the supercomputer and the hand grips. Alan Shearer is in a box slung around my neck with string, and the laptop – minus its battery – along with everything else I brought, is in my backpack. I tighten the straps on my shoulders. The laptop battery is in my jeans pocket. I pat myself down, like a commando going on a raid.

Picking up the tins of creosote, I splash it around the perimeter of the tech lab, watching it form into pools, and then pour a single line of the sticky liquid from one of the pools to near the buckets.

Along the corridor from the tech lab is a locked office. By now, what I do next is becoming almost normal. Grabbing a fire extinguisher from the wall, I smash it repeatedly into the door handle till it gives way.

I’m staring at the phone on the desk. It’s one of those old ones, with the rotary dial on the front. As soon as I make the call, there is no going back, and I dither and stare for what seems like ages. My palms are moist and my breathing is shallow, so shallow that I don’t think I’m going to be able to speak on the phone.

I swallow hard and pick up the bit you hold. Without hesitating further, I put my finger in the hole labelled ‘9’, drag the dial around and release it. I do this twice more.

Almost immediately, my call is answered.

“Emergency. Which service do you require?”

“Fire. Please.”

“Please hold the line I’m putting you through now.” There’s a short wait, and then:

“Fire Service. May I take your name and number please?”

It’s written in the middle of the dial, so I read it out: “I’m, er … Jamie Bates, and the number is Culvercot 212232.”

“And where are you calling from?”

“46 Chesterton Road.” A lie, but I’m guessing they won’t find out until later. And besides, lying – among all the other crimes I’ve committed – is hardly worth worrying about.

“Where is the fire, caller?”

“I’ve seen smoke and flames coming from Culvercot Secondary Modern. Ground floor, what they call the technical lab.”

“Are you in any danger, caller?”

“No.”

“And are there any people present in the building?”

“No. At least, I don’t think so.”

As soon as she says a fire engine was on its way, I have about three minutes because the fire station is on this side of town, and it’s a straight run. But I need the flames to take hold and destroy the computers before they put the fire out.

Arson – another one to add to the list.

Back at the lab, and it stinks of creosote. I stand in the buckets, one foot in each, I’ve got the wire hand grips ready and I just … freeze.

I just cannot do what I need to do.

I don’t know how long I’m standing there, but when I hear the sound of the fire engine at the top of the road, I’m snapped out of my daydream. The siren is going full blast, and now I have only seconds.

I quickly copy the line of letters and numbers from the top of the black box on to the screen, and add the coordinates for time and place.

I’ve got the laptop battery in one hand and the steel wool in the other, held by plastic tongs, and I bring the two together, so that the steel wool bridges the gap between the battery’s contacts and …

POW!

There’s a spark, more than one, and the wool catches fire for a few seconds.

That’s all I need. I crouch down and spark the wool again, and this time the creosote catches fire, but much, much faster than I had expected. There’s a burst of flame in my face as I’m bending over and I can smell my singed eyebrows. The fire dances along the trail of creosote and seconds later has reached a big pool of the flammable liquid which bursts into flame with a whoomph and ignites all the rest of the creosote around the room.

I’ve barely had time to stand up again and already the flames are surrounding me, getting hotter by the second. I’ve got the wires gripped in each hand, and I reach out for the ‘enter’ button on the keyboard, but in my panic, I knock the keyboard off the desk, where it dangles by its cable.

Now, as well as the light from the flames, there’s a flashing light of the fire engine that has pulled up only metres from the windows, and I hear a voice shouting “Sarge! There’s a boy in there! A boy, in the room!”

I’m groping through the thickening smoke for the swinging keyboard, and I’m coughing and coughing, and crouching down with my feet in the buckets, because the filmy, wobbly bubble seems smaller than ever. When the window smashes, there’s an even bigger ball of flame as the inrush of oxygen from outside feeds the fire, and I’m sure I can feel my skin burning, and I’m stabbing at the keyboard with my fingers, hoping to hit ‘enter’, and that’s when I collapse and don’t feel anything more at all.