She spat in my face and called me a murderer while the brother punched me in the side of the head. A uniformed officer intervened before things went any further, but the incident taught me two things. One, never rely on the support of people you're trying to help. As politicians have often found out to their cost over the years, the hand that pats you on the back one day can just as easily grab you by the balls the next. And two, never rely on anyone else for support either. In this world, you've got to get used to the fact that, in the end, you're always on your own.

No blame was ever officially attached to me over the killing of thirty-three-year-old Darren John Reid (who, it turned out, had a grand total of twenty-nine convictions, including eleven for violence, four of which related to his missus), but it might as well have been. I was taken off any further firearms duties (and have been to this day); banned from keeping guns privately; and my path up the career ladder slowed down one hell of a lot over the next few years. Crime, it seems, only pays when you're a criminal.

I'm not a bad man, whatever those who like to sit in judgement may think. When I started out I really did believe I could make a difference. My sole motivation was to take the bad guys off the street and bring them to account for the crimes they'd committed. After the Reid shooting, I slowly stopped caring. I suppose I finally realized what all defence lawyers know: however well intentioned its designers may have been, the law in practice only serves to help the criminal, hinder the police, and ignore the victim.

Having got to a point when I was as cynical as that, it was only a matter of time before I fell in with the wrong company. The wrong company being, in my case, about as wrong as you can get, although when I first started doing business with Raymond Keen, one of North London's more colourful entrepreneurs, I wasn't to know quite how far it would go.