I would be lying if I pretended that I hadn’t thought about killing McGee. I never forgot about him for more than a few hours, and then he would come sliding back into my thoughts like an eel disturbing calm water. At least a couple of nights a week I lay in bed with my arms neatly tucked underneath the blue-striped, fraying counterpane so I couldn’t see the raised unpleasantness of the scars, and – just before I drifted off to sleep – I would think of all the different ways that I could do it. Sometimes this calmed me down, like a sleepy little lullaby of revenge, and sometimes I had to stop thinking about it because it inflamed my nerves too much.

I thought about tricking him into drinking a pint of beer full of crushed sleeping pills and then pushing him into the Lagan so that he sank like a stone and never came up; or monkeying with the brakes on his car and watching him go skeetering across the road slap bang into a brick wall; or binding his arms and legs together very tightly before turning on the gas in his kitchen, sealing the door and then walking out to inhale the clear, crisp, sweet air. That wasn’t the way feuds were usually settled in Belfast: it was usually with a bullet or a pipe bomb, but I didn’t have a gun and I wasn’t a pipe bomb type of person. I didn’t want to meddle around with explosives and wires and end up blowing half my own arm off. I preferred something sneakier.

There’s something unsettling about looking into another person’s dreams of revenge. It’s like taking a peek into the friendly neighbour’s living room and seeing all the rubbish from the previous year strewn across the carpet. Revenge squats there among the steaming entrails of unfinished business, a clump of the bad stuff in a corner of the human heart.

But I won’t say sorry for it. What bothered me about those characters in The Stranger and Crime and Punishment, if I have to admit it – what made me want to button up my overcoat, check my watch and say ‘thanks fellas, I’ve enjoyed your company, but I’ve got to be somewhere else in five minutes’ – was that they killed people who didn’t fully deserve it: that Arab on the beach who hadn’t done much to Meursault yet apart from flash his knife, and that mouldy oul moneylender who was only trying to get by herself, scraping a living from one of those freezing Russian flats, not to mention her harmless half-sister.

I was contemplating killing someone who did deserve it, though. In fact, I couldn’t really think of anyone who deserved it more than McGee. There were times when I thought that I could never really rest until he was gone for good.