Simon Kernick - Severed

I don't look back but keep running towards the seemingly impenetrable mess of brambles at the end of Alannah's garden. I charge straight through them, ignoring the scratches and the sound of the cotton of Lucas's polo shirt tearing. A set of rusty iron railings appears out of nowhere, and I vault over them, getting a faceful of brambles in the process.

I land on a narrow footpath that runs parallel to a high mesh fence topped with barbed wire marking the border of railway property. The fence is covered in tangled foliage and a sign says KEEP OUT in bold lettering with a picture of a menacing black skull on each side of the wording. There's no immediately obvious way in, so it becomes a choice of left or right.

Unfortunately, the choice is made for me when I hear the unmistakable sound of dogs barking – big dogs, too – followed a second later by the rapid tattoo of paws on concrete. Getting closer.

I just have time to bemoan the fact that even my favourite animals have now joined the ranks of my enemies, then I'm off in the opposite direction, knowing there's no way I'm going to outrun them. I run across the road the viaduct crosses and keep going along the footpath on the other side. It begins to rise steadily, which does not bode well, and I can hear the barking getting closer, partly drowned out by the sound of an oncoming train. Through the mesh in the fence I can see that it's a slow-moving freight pulling cart after cart filled with building aggregates. The path's getting pretty steep now and my lungs feel like they're burning up. I'm fast over short distances, even uphill, but I'm not going to be able to keep up this pace for much longer.

There are two young kids, barely ten, messing about with what looks like an old fridge on the strip of wasteground that runs alongside the track. They are doubtless up to no good, but I don't care about that. What I want to know is how the hell they got in there.

And then I see it, about ten yards further on. A small, kid-sized hole at the bottom of the fence. I force myself to slow down, the patter of angry paws right behind me, then at the last second I do a hard turn and dive bodily through the hole, scrambling to my feet on the other side and running wildly for the track. The freight train's almost passed now, but even above the steady, rhythmic clatter of its wheels I can hear the excited panting of a dog. He's feet away and gaining, and I know there's no way he's not going to get me.

As I reach the raised shingle on which the track sits, he lunges. His teeth get an iron grip on my leg, but I've still got just that little bit of momentum, and as the final cart passes directly in front of me I jump skywards, getting one flailing arm on the cart's lip, and a foot on the buffer. I swing round so that I'm hanging on to the rear of the train, and the dog, a big Alsatian, swings with me. But the thing is, he wasn't expecting this and I was, and he just keeps on going, releasing his death grip at the same time. He flies off, does a very effective rolling landing, then jumps to his paws and stands there with his tongue lolling out, watching me disappear slowly into the distance.

I look towards the fence and catch sight of several men running on the other side of it. They stop as they see me come trundling past at a leisurely twenty miles an hour or so, which is when I see that they're in uniform. I can't resist giving them a little wave, and then they're gone, as the train goes over the viaduct and starts to turn a corner.

Once I get my breath back, I decide that it's surprisingly relaxing hanging on to the back of a train on a warm summer's evening, with the breeze in your hair. Darkness is falling fast and a three-quarter moon the colour of melted butter sits high in the darkening sky. There are no stars, the haze of neon lights that spreads for miles around smothering them like a blanket, but there's something beautiful about the way the city seems to come to life at night, and something exhilarating too about outrunning people who want to do you harm. It seems right now that the whole world seems to want to do me harm, yet in those moments I feel the best I've felt all day.

But I've got another mystery on my hands now, because it's obvious that Alannah didn't call people to come and kill me. She called the police to come and arrest me instead. Which leaves two very important questions.

Number one: Why?

Number two: Just who exactly is she working for?

I'm on a quiet street in Kilburn roughly a mile or so from where I grabbed a lift on the train, and a few hundred yards from where I jumped off it. As I walk along it, Lucas's torn shirt flapping in the breeze, I review my options.

Time is not on my side. It's twenty to nine. Lucas dropped me at Holloway Road tube more than two hours ago. He will have spoken to the police by now, and after what I'm sure he's said, they're going to be looking for me with some urgency. So I really am going to need to make Eddie Cosick's acquaintance soon. In other words, tonight. The address book I discovered at Ferrie's place is still in the pocket of my jeans, thank God, and it seems that Ferrie knew about Cosick too, because when I look the name up I get an address in W8, which tallies with Alannah's description of it as being in Notting Hill.

But as I walk, I consider for the first time the possibility of handing myself in and actually telling the police the truth, the rationale being that they're going to catch me eventually so it would be better to pre-empt them. But I swiftly discount this. I'm too heavily implicated in the events of today: the shootings at Ferrie's place and the chaos at the brothel. As well as this, there's still the possibility that there are copies of the DVD out there linking me to Leah's murder.

At the moment, visiting Cosick is my only option. It's extremely risky, but there's nothing I can do about that. I do, however, have a real stumbling block. I'm unarmed. Which means I'm going to have to speak to Lucas. I genuinely don't want to drag him back into this, but I can't see how I can avoid it.

I use the mobile he supplied me with to make the call. He answers on the first ring, as if he's been sitting there waiting for me.

'The police have only just gone,' he informs me. 'I was going to phone you. I'm sorry, Tyler, I had to tell them that we were doing the job today on your behalf.' He sounds genuinely gutted.

'Don't worry,' I tell him, 'I know you had no choice. How much information did you give them?'

'I tried to keep it to a minimum. I said you approached us out of the blue this afternoon about a job. You wanted a track on a briefcase. You didn't tell me what was in it, and I didn't ask, because I trust you. I gave Snowy the task of following the case, and told him to keep me posted with progress calls every fifteen minutes. We got two, then they stopped. Me and you parted company, and I got on with some other work, namely a job in Islington, assuming that Snowy would phone me back. I was getting worried but obviously didn't think it would be anything too serious, so didn't bother reporting it, and then, bang, the next thing I know, the police are on the phone announcing that he's dead.'

'Won't they know you were talking to him on your mobile shortly before he died?'

'Sure, but when they triangulate my location, they'll see that I was in Islington just like I said, a good two miles away from where they discovered Snowy.'

'So you're in the clear, right?'

'The only possible concern is if someone saw me pick you up after the brothel fire, and can place me at the scene, but I'm hoping I'll be all right. There are no public CCTV cameras on that street. I checked.'

'Did they ask you anything about the fire?'

'No, I think they believed my story. There was no reason not to. But obviously they want to speak to you. They said that if you made contact with me, I was to call them straight away.'