On this warm night the city seemed turned inside out. The pavements in front of smeared fast-food shops were crowded and when we slid past a scruffy slice of tree-lined green space there were dozens of people sitting or lying on the grass, and an icecream van as well as a hot-dog cart doing good business. An ambulance’s blue light prickled in my mirror and I pulled in to let it sweep past. Faster-moving traffic instantly flooded into the space left in its wake. Faces loomed at my windscreen as I stopped at a crossing and I checked with my right elbow that the self-locking button was down. My car was a capsule of safety, weaving through the mayhem, with Cassie fast asleep in her seat.

I let myself in to Penny’s house and carried Cassie upstairs. When she saw her bed she stretched her arms out, as if to embrace its security. Her head flopped on the pillow and she gave a sigh. I settled the quilt round her small shoulders and sat on the edge of the bed for a minute or two, in case she needed anything. But I thought she was already dreaming. I turned on her night light and before I drew her curtains stood looking down at a black angle of the canal. Three pale reflections of windows shivered on the surface; just beyond them the towpath was a faint streak of dusty earth that led past the dense darkness of undergrowth and disappeared into the utter black beneath a bridge. I drew the star-patterned curtains against whatever lay out there.

I rang Matt to tell him where I was and he said there were no worries, he’d go to sleep in Lola’s room if he felt tired. I made myself a cup of tea and sat down at the kitchen table with the weekend newspaper supplements. It was 1 a.m. when I heard a black cab ticking outside.

Penny and Evelyn came in with a waft of smoky air and the exaggerated movements of people who have had plenty to drink. Evelyn came straight to me and put her hands on my shoulders, then leaned right down so that waves of hair flowed either side of my face. She smelled of the party.

‘Fast asleep,’ I said.

‘There,’ Evelyn said to Penny. ‘I told you everything would be fine.’ There was a smile of vindication in her voice, but at least it was a smile. Evelyn’s mood had somehow swung into the benign sector in the intervening two hours.

‘Thanks to Sadie,’ Penny answered.