The boats were still in the sink but the puddles on the floor had almost evaporated. A little knot of neighbours was gathered in the yard, and Penny was directing them to take a street each and knock on every door. Her eyes were staring and her face was a terrible dead white.

‘Jerry? Could Jerry have taken her?’ I shouted. It was only on Friday that I had seen him singing at the gig. It felt like five years ago.

‘No. Jerry’s coming. He hasn’t got her.’

Two more policemen came round the side of the house, moving with massive calm. The neighbours fanned past them. I ran, hearing Paul in my wake, out of the yard and down the alley to the canal towpath.

There was no one there. The water was an unrippled sheet of khaki under a layer of dust. The grass at the land side had recently been cut and it was baked to a light toast-brown and scattered with empty cans, polystyrene food trays and dog mess.

I stared wildly up and down the path, then knelt down at the water’s edge, trying to see into the depths. All I could actually see were Cassie’s limbs flailing and her mouth, open to scream, filling with water as she sank out of sight.

‘Oh, please, God,’ I whispered.

Paul’s hand touched my shoulder. ‘You go that way, I’ll go the other.’

I scrambled up and made off towards the lock. The gasometers loomed against the whitish sky. The band of shade beneath the bridge dropped across my face and I touched the crumbling brickwork. There was nothing on the no man’s land under the opposite pier except broken glass and half-bricks torn up from the playground next to the bridge. I ran on and came round the corner before the lock. A fisherman was sitting there, his beefy bare arms and chest livid from the sun. ‘Have you seen …?’ I began but he cut me short.

‘That kiddie not found yet?’ I shook my head. Penny had been here before me, of course. The man quickly reeled in his line and put his rod in its cradle. ‘I’ll walk on up this way for you,’ he said.

‘Thank you,’ I panted. The sight of him stirred something in my mind. Whatever it was glimmered like a fish in deep water and I pressed my fists against my temples in a vain attempt to hook it.

I ran back in the other direction. Paul was shouting the question to a narrowboat full of startled people and the boatman cut the engine in order to hear him. In the quiet, the prow of the boat swung gently towards the near bank.

‘Anyone seen her?’ the boatman called to his passengers. They shook their heads, smiles fading on their faces.