He wants to kill me.

I don’t know if you’ve ever been in a situation where you had to face that? It’s a hell of a thing to realise. All the good things you’ve tried to do in your life, everything you thought was right and important and moral, none of it matters a damn. You’re on your own, and the only question is, can you do what it takes to save yourself? To tell the truth, it’s surprisingly liberating. If you survive it.

The odds didn’t look good. He had a gun; I was stuck on an icy platform ten metres up. But you see the world differently when you don’t have a choice — like a cornered animal.

A little way from the platform, one of the old coal cars dangled from the cableway, like a mine car without wheels. Probably two metres away — two metres of space with nothing underneath except a long drop on to ice, and a man waiting there to kill me. In normal circumstances, I’d never have dreamed of trying to make it. I didn’t even know if the cable would hold, or the rusting arm that the car hung on. But these were pretty far from normal circumstances.

I got to my feet, crouching so he wouldn’t get a clear shot. The gap yawned in front of me, hypnotising me. I remembered something I’d read about basketball, that the mistake most people make is to focus on where they might miss, rather than on the hoop itself. I stared at the coal car, concentrating like mad. It still looked a long way off.

Our minds are fickle things. Even on the highest diving board, there’s a moment your attention wanders and you forget the big drop you’re so frightened of. That’s the moment to go.

I jumped.

In a perfect world, I’d have worn something more flexible than a heavy coat and thick trousers; I wouldn’t have had such stiff legs, or numb hands. But then, in a perfect world I’d not have been there. All I could count on was the adrenalin charging me up, and the focus that comes when there’s no alternative.

I slammed into the side of the car and just managed to hook my arms over the edge. It was like trying to clamber into a boat without capsizing it. The more I pulled, the more it tried to tip me out. My legs kicked air; the rusted metal scraped holes in my jacket. Too late, I realised the whole contraption was designed to swing ninety degrees to tip out the coal.

But twenty-five years out in the cold had gummed it shut. I pressed my arms against the rim, heaved — and was stuck. The radio on my chest had caught on the lip. I heaved some more. Velcro tore; the radio came loose and fell. I popped up like a cork, wriggled forward and somersaulted over the edge with a thud. The car swayed; I waited for something to snap.

It held.

The whole manoeuvre had taken a matter of seconds. Too quick for my enemy to get off a shot, but not by much. I heard the shot and the impact almost simultaneously. The coal car rang like a bell, trembling all around me, but the metal — good, Soviet steel — turned the bullet away.

The sound died. Cowering in the bottom of the coal car, all I could see was the sky, and three cables dissecting it. The bullet’s echo rang in my ears, mingling with the moan of the wind in the wires.

Had he run out of bullets? I counted back in my head. There might have been five shots — I couldn’t think straight enough to be sure — or there could have been four.

Five would be good news. Four was a problem.

Do ya feel lucky? Clint Eastwood enquired.

The metal under me shivered again. Not the hard clang of an impact, but a steady vibration. Tremors were coming through the wire, down into the bucket. Feet climbing the ladder up the pylon.

What could I do to stop him? If he tried to jump, we’d probably both tip out. My hands were so numb now I couldn’t have held a football. Second-degree frostbite, the doctor in my head diagnosed, though at that moment it was a long way down my list of concerns.

The tremors stopped. I had to look. I raised my head over the edge of the bucket — and there he was. The wind puffed out his parka so he seemed more massive than ever, a yellow monster with black eyes, crouching to spring at me.

We stared at each other. If we’d both reached out, we’d almost have touched, but even that close I couldn’t see anything of his face. The hood, goggles and ski mask hid it completely.

‘Who are you?’ I shouted. I don’t know if he heard. The wind whipped my voice away from me.

He spread his arms against the posts of the pylon and leaned back, ready to throw himself at me. Then paused. I saw him look around, checking something.

I’m not a brave man. That face — the mirrored goggles, the slit mouth and what he wanted to do to me — I couldn’t look at it. I must have closed my eyes. From down on the snow, I heard the radio squawking. Eastman at last — but too late, and nobody to answer it.

The vibrations started again. Not the hard impact I’d expected; the gentle knock of feet on a ladder. I opened my eyes.

He’d gone. The vibrations faded, until I couldn’t feel them at all. Only the coal car rocking gently in the wind.

I lifted my head as high as I dared and strained to listen. I thought I heard footsteps, crunching quickly through the snow. Then silence.

I still didn’t dare look. I imagined him waiting behind a rock, my own gun trained on the coal car, ready to shoot the minute I put my head above the parapet. Four shots or five? The first thing Greta teaches you at Zodiac is to count your shots, but it’s harder when it’s your own gun being shot at you. And what if he had his own weapon?

More footsteps, punching through the dry snow at a run. I huddled lower in the coal car.

‘Doc?’

Eastman’s voice. I was shivering so badly I could hardly haul myself over the edge of the coal bucket. I pulled myself up, resting my chin on my sleeve so that the steel didn’t freeze to my skin.

Down below, through the wooden girders, I saw Eastman in his red coat. He had his back to me, walking towards the town.

‘Here,’ I called. My teeth were chattering so hard I could barely speak. I cursed myself for dropping the radio. I tried again — louder, but still not enough to carry.

Eastman turned. Hope soared; I waved like an idiot. But he was looking at the ground, and it’s hard to see ten metres up when you’ve a fur hood around your eyes. He turned away again.

In a fury, I thumped my frozen hand against the coal car. The metal rang: a low, mournful noise like a funeral bell. This would be my coffin. Frozen in the dry air, I wouldn’t rot: I’d stay preserved for centuries, maybe until global warming made coal mining economical again and some future miner got the shock of his life when he dumped the first shovelful of coal in the bucket.

I pounded on the steel. I kicked and thumped. The coal car swayed. Eastman was almost behind the barracks now. When he vanished, that would be that. The angels could sing, and Francis Quam would write an empty note to my daughter in Dublin.

They say low frequencies can travel for miles. I don’t know how far my banging went, but it was far enough. Eastman heard. He turned, and this time — glory be — he looked up. I waved a limp arm at him, saw him start to run. I slumped down in the car.

Shock, cold, adrenalin, terror — I had it all. I could hardly hold on for him to climb the ladder. At last his face appeared over my steel horizon.

‘What the hell are you doing in there?’

Eastman stood where the monster had been a few minutes before, so close we could almost touch. But those last two metres were a problem. I couldn’t jump back to the pylon — the coal car wasn’t a stable platform, even if I’d had the strength — and the idea of me swinging along the cable like a monkey was laughable, if I’d been in the mood for humour.