It was a typical piece of middle-class naivety, really. He was holding half a pound of speed he was meant to be selling to a contact of his, but the contact, deciding it was easier to steal the goods rather than buy them, set him up. On his way over to the contact's flat, three of the guy's mates ambushed him in the stairwell. However, since Danny hadn't yet paid for the stuff, he was loath to give it up. A very one-sided battle ensued and Danny ended up with a fractured jaw, smashed cheekbone, severe concussion, and God knows how many busted ribs. And he still lost the speed, which, by all accounts, had to be prised from between his broken fingers.

He was in hospital three weeks altogether, which, when you consider it was on the NHS, gives you some idea of the extent of his injuries. It really threw the cat among the pigeons as well. His dad seemed to think that, because it had happened on our patch, I should have known something about his activities and put a stop to them, or at least told him about them. So he turned against me. Danny's mum followed suit, being one of those people who are incapable of their own opinion. The thing was, I could have lived with that, no problem. I'd never liked either of them much anyway. The problem was Danny. Once he got out of hospital he wanted revenge on the man who'd set him up. He was also worried because the guy he'd bought the stuff from now wanted paying as well. In fact, he wanted a lot of favours and the only person he knew who was in a position to grant him any was me. I'd always got on well with Danny, even though he'd never been able to hide his dope-dealing activities from me, and I genuinely liked him.

So when he came to me begging for help, I said I'd do what I could. The guy who'd sold him the speed was a pretty low-level player, so a quick threat of prosecution and the possibility of worse got him out of the picture. It was the revenge thing that represented a problem. Danny wanted me to help him take the guy out, though help wasn't exactly the operative word since it looked like I would be the one doing most of the work. Danny was only five feet six and of proportionate build, so he wasn't what you'd call a useful ally. He wanted to ambush the guy in the same way he'd been ambushed, and return the kicking, but I talked him out of that one. I don't even know why I agreed to get involved at all. I could have just told him to cut his losses and be thankful that he no longer owed the other guy money, but I didn't. Maybe it was a pride thing. Maybe I wanted him to look up to me, I don't know.

Anyway, I devised a compromise. A couple of months earlier I'd uncovered about fifty ecstasy pills in an unrelated search of a suspect's premises. Because we already had the suspect bang to rights on about a dozen other charges, I'd put the pills in my pocket, thinking they might come in useful at a later date, not so much as a commodity – even in those days there was a lot of controversy over the effects of E, and I didn't want anyone dropping dead of anything I sold them – but of course they had another use, and that was helping put away criminals who were proving particularly hard to pin down for their crimes. I'd never planted anything on anyone before, but I'd heard about enough cases to know that it usually worked. If it was carried out properly.

Which was the difficult part. The guy, whose name was Darren Frennick, didn't tend to leave his flat very much, apart from to do the odd deal, and we needed uninterrupted access. We thought about it for weeks, racking our brains for a way to get in there, before we came up with a simple yet foolproof solution. Frennick was an ugly bastard but, like all young men, he had a healthy sex drive. I knew a girl at the time who was a professional escort and who could be trusted with difficult jobs. So what we did was this. Having paid her a substantial amount, funded by Danny, and given her the tablets, we sent her round to the flat. She knocked on the door, and when Frennick answered she told him she was his escort for the evening. He started to claim ignorance, but she was a good-looking girl and he didn't want to look a gifthorse in the mouth, so he invited her in and kicked out the couple of mates he'd had round there at the time.

As we'd guessed, he didn't want to escort her anywhere, preferring instead to get straight down to business. But within seconds of his amorous advances she was claiming she wasn't that sort of girl and an escort meant just that. He asked her what the hell she was on about and continued with his pawing, which was when she showed him some of her kung fu moves. One series of ferocious blows and kicks later and he was out cold on the floor. Quick as a flash, she used a pair of tweezers to remove the packet of pills from her handbag. She brushed them briefly against his fingers, then threw them under his bed. He was coming round by that time so she ran out of there, shouting and screaming, and immediately phoned the police on her mobile phone, saying that this man had tried to give her some pills and rape her. She gave the address and his first name, and the cops, knowing who he was, were round there like a shot. By which time, of course, she'd made herself scarce.

Five minutes later she called the police again, saying that she was sorry, she didn't want to get involved in pressing charges against the guy, but she had seen him put the pills back under his bed. Despatch passed this information on to the officers on the scene, who'd entered the flat through the open door. A dazed and bloodied Darren Frennick was arrested and remanded in custody. He ended up serving nine months for supplying Class A drugs, which Danny didn't feel was revenge enough, but which I assured him was the best he was going to get.

And that should have been that. Except that it wasn't. I don't think Jean ever found out the full story, but somehow she got wind of the fact that I'd used an escort girl to set Frennick up, and worked out that this was a side of me she'd never seen before and one that she didn't particularly like. Things became strained after that, Jean repeatedly asking me if I'd ever slept with prostitutes, and not believing me every time I said no. First, the living-together lark went on hold; then a couple of months later, the relationship followed suit.

By rights, I should never have forgiven Danny for fucking up what will in all probability turn out to be my one chance of getting hitched, but he was so grateful for what I'd done, and felt so guilty for the problems he'd caused, that I found it difficult to hold it against him. Jean and I never really saw each other again after that. She met this chartered surveyor from up north and moved to Leeds with him, but Danny and I continued to keep in touch. Occasionally we did business together. One time I sold him a couple of kilos of dope I'd liberated from its wrongful owner. He tried to move it on but ended up selling it to undercover Drugs Squad officers and getting nicked instead. They leaned on him hard, trying to get him to name his source, but his experience with Darren Frennick had hardened him. He feared prison – who doesn't? – but he kept quiet, even though they told him that co-operation would surely mean a lighter sentence. He ended up doing eighteen months.

Danny was not the luckiest man in the world; nor was he, in criminal terms, one of the best at his profession, but I trusted him absolutely, and there are very few people I can say that about. That's why I took him with me when I went off to kill three men. Because I knew he'd keep his mouth shut.

He rented a basement flat up in Highgate, not too far from the cemetery, and it was twenty to six when I finally rang his doorbell. He opened the door slowly, keeping the chain on the latch, and poked his head round. His face was pale and there were bags under his eyes. He looked like a man with a lot on his mind.