The vein stands up, proud and inviting. The syringe sits on the bedside table, the new orange needle gleaming expectantly. One of the small benefits of being a doctor and an addict is that clean needles are easily available, and the risk of HIV and hepatitis B or C infection is low. I had used a green needle to draw up the drug, a needle that can reach right to the bottom of the ampoule, so that not one drop will be missed. Beside the syringe lies the empty packet of Cyclimorph; the red and blue packaging is so distinctive to me that if it was lying on the road a mile away I would spot it.

Everything is quiet, the doors are closed, the curtains pulled, it is all dark except for the bedside lamp. I am alone in the house; there is no glamour here, no drama, no heroin chic—it’s just a selfish, venal, deceitful, squalid, solitary vice.

I tap the vein lightly with my forefinger, testing the bounce. The vein is engorged and will be easy to access, little chance of missing the vein and the drug leaking into the subcutaneous tissues, which would leave a painful and visible bruise and, even …