‘He says he did.’ Aidan paces the room, back and forth. ‘Whoever he saw claimed she didn’t know me. She’d never heard of me.’

‘What do you mean, “whoever he saw”?’ A cold ripple of panic passes through me. ‘Didn’t he check . . .?’

‘She showed him her passport and driving licence. The woman he spoke to was Mary Trelease. His description of her fitted the one I’d given him, detail for detail.’

‘Aidan, I . . .’

‘So, that’s it.’ His voice is loud and forced. ‘They don’t believe me. It’s over as far as they’re concerned.’ He lets out a humourless laugh, jeering at himself. ‘No one’s going to come and arrest me in the middle of the night, no one’s going to cart me off to jail. We should celebrate.’

‘Aidan . . .’

‘Three cheers for me.’ He looms over me, a droplet of his saliva landing on my face. ‘Why don’t you crack open a bottle of champagne? It’s not every day your boyfriend gets away with murder.’

I didn’t meet Aidan by chance. I planned it, though it took all the self-discipline I could muster to put the plan into action. On the twenty-second of August last year, I got up, threw on the T-shirt, jeans and flip-flops I’d worn every day for the past two months, and got into my car without giving myself time to think or change my mind.

I had Aidan’s details written on the back of a receipt in my jeans pocket. I knew where Seed Art Services was, didn’t need reminding, but having the address with me, written in black and white on a piece of paper, made it harder for me to avoid what I knew I had to do. A positive prescription, my books call it. I’d tried the technique a few times and it seemed to work.

I parked at the bottom of Demesne Avenue, where it gives way to the unmade road that runs alongside the river, and walked under the overhanging trees, counting my footsteps to take my mind off the task ahead. I’d got as far as forty when I reached the small, flat-roofed grey-brick building, with a wide wooden door that had buckled at the bottom where the wood was cracked and blistered, flaring out like a skirt. The door stood slightly ajar. On its inside were two large iron hinges and two even bigger bolts. Rust clung to them, looking like an exotic species of chestnut-coloured moss. Had the door been closed, I’m not sure I’d have been brave enough to knock.

Saul Hansard, my boss at the Spilling Gallery until two months earlier, had promised me Aidan would be pleased to see me. He could have told me thousands of times and I wouldn’t have believed him. Wherever I went, I felt unwelcome. I stared at Aidan’s open door and listened to the music that was coming from inside the workshop: ‘Madame George’ by Van Morrison. I knocked and waited, feeling my heartbeat in my throat, staring in through the long rectangular pane of PVC-framed glass on my right—the only window, as far as I could make out. It ran the length of one side of the building. Through it I saw neon strip lights, a concrete floor, dozens of planks of wood, some plain and some painted, leaning against a wall; two large tables, one covered with what looked like velvet cloths in different colours, a small radio with a paint-spattered aerial. On the other table there was an enormous roll of brown paper, scissors, a pair of pliers, a Stanley knife, lots of what looked like catalogues in a pile, a few bottles of glue and tins of paint.