‘It’s the City,’ said Pierre darkly; ‘they keep the money for new pipes. They kill my friend. What do you want?’ he added, opening a package and piling some white powder into a spoon with the corner of a razor blade.

‘Um . . . a gram of smack,’ said Patrick casually, ‘and seven grams of coke.’

‘The smack is six hundred. The coke I make you a price: one hundred a gram instead of one-twenty. Total: thirteen hundred dollar.’

Patrick slipped the orange envelope out of his pocket while Pierre piled another white powder into the spoon and stirred it, frowning like a child pretending to make cement.

Was that nine or ten? Patrick started counting again. When he reached thirteen he tapped the notes together like a shuffled deck of cards and tossed them over to Pierre’s side of the mirror where they fanned out extravagantly. Pierre wound a length of rubber around his bicep and gripped it in his teeth. Patrick was pleased to see that he still had the use of the volcano cone in the hollow of his arm.

Pierre’s pupils dilated for a moment and then contracted again, like the feeding mouth of a sea anemone.

‘OK,’ he croaked, trying to give the impression that nothing had happened, but sounding subdued by pleasure, ‘I give you what you want.’ He refilled the syringe and squirted the contents into a second pinkish glass of water.

Patrick wiped his clammy hands on his trousers. Only the need to make one more tricky negotiation contained his heart-exploding impatience.

‘Do you have any spare syringes?’ he asked. Pierre could be very awkward about syringes. Their value varied wildly according to how many he had left, and although he was generally helpful to Patrick when he had spent over a thousand dollars, there was always the danger that he would lapse into an indignant lecture on his presumption.

‘I give you two,’ said Pierre with delinquent generosity.

‘Two!’ exclaimed Patrick as if he had just witnessed a medieval relic waving from behind its glass case. Pierre took out a pair of pale green scales and measured the quantities Patrick had requested, giving him individual gram packets so that he could keep track of his coke consumption.

‘Ever thoughtful, ever kind,’ murmured Patrick. The two precious syringes followed across the dusty mirror.

‘I get you some water,’ said Pierre.

Perhaps he had put more heroin than usual in the speedball. How else could one explain this unaccustomed benevolence?