Panting, I looked back up just as my pursuer arrived at the top of the last flight of steps. 'Oops,' he said playfully, waving the knife in front of him like a wagging finger. 'Bad move.'

A small part of me felt like giving up there and then. Admitting the fact that I wasn't going to make it out of there and throwing myself at his mercy. Except that I knew there wouldn't be any.

And it was only a small part of me. Self-preservation won through, and as he jumped down the last of the steps I turned and ran for the fire door in the corner – the only way out. I had no idea whether or not it was open, or where it led to, just relied on my instinct to live to keep me going. Running right into it, I pulled down the metal handle, felt it give, and half fell, half scrambled through into a cold and cavernous underground car park.

He was still with me, almost as if he was glued to my slipstream, but this time I took the offensive and turned and slammed all my weight against the fire door, catching him by surprise and trapping his knife arm in it.

But before I could do any real damage, he pushed from the other side and, being one hell of a lot stronger than me and with momentum on his side, he sent it flying open, and me stumbling backwards.

I turned and ran through the dimly lit, silent car park, not knowing where I could turn. Ahead of me was one of those big roller doors that I knew was either the entrance or the exit, but it was shut. My legs felt weak and I just couldn't seem to get the pace up to put any distance between us – the bastard was like some kind of automaton – and I'd barely gone twenty yards before he leapt on my back for a second time, sending me crashing into the concrete.

Sitting astride my back, he yanked my head up by the hair and I knew in an instant that he was going to cut my throat like some kind of animal. I bucked and thrashed as the knife suddenly appeared right in front of my face, and managed to pull free a hand. I immediately grabbed him by the wrist, forcing the blade away from me. I also jerked my head forward, trying to bite him, but his grip on my hair was too strong. This guy had the better of me, and both of us knew it. My arm was shaking with the effort of holding the blade away, and right then my life expectancy could be measured in seconds.