‘The ghost was rushing forwards towards David. As he came he grew bigger and bigger and bigger, until he was like a lorry charging through the pipes. David screamed and the ghostly boy opened his mouth and screamed back. But his scream wasn’t the scream of a child. It was the scream of an old, old man. “Come back, come back,” screamed the ghost in his cracked old voice. “Don’t leave me. Don’t go!”’