‘He sent me a letter recently, via my sister. That included the photograph. My mother had changed our family name to Rogers soon after he was sentenced, and moved us away from the north-east down here. That kept the press away, but somehow he’d tracked her down. After she died, Susan got married and I changed my name again, to Jakes, my maternal grandmother’s name. But in the last year or so my father managed to find out where Susan was. He wrote to her, a couple of times,’ he said, staring around the room. ‘He wanted to meet us both. I wasn’t ready, the whole thing just made me really anxious. Neither of us were keen.’

The two detectives sat back and looked at him.

‘In some ways this raises more questions than it answers,’ Gillard said, turning briefly to Hoskins. ‘According to your story, you saw a man who may have been dumping a body. Don’t you think it’s a bit of a coincidence that the very person who stumbled across a body in the middle of the night happened to be the victim’s son? Especially if, as you maintain, no arrangement to meet up had been made.’

‘What do you mean?’

‘I think it’s pretty obvious,’ Hoskins said. ‘We’re detectives, and we add up the clues. You already had the opportunity to kill this man, given that you were found by the body. Now you say he is your father, we have a motive too.’

Michael Jakes was released on police bail. He had to catch the bus back home, as the police had retained his bicycle in the search for evidence; and he was told to phone them from home every evening. The police seemed to think it was a coincidence that he had stumbled across the same car that he had seen that first night on the bridge. But it wasn’t that much of a coincidence. He had had a feeling that he was on to something right from the start, from the first splash. It was a premonition that came into his dreams that very night. Nietzsche had come to him, in the darkness: You will be the instrument of salvation, not just for yourself but for others. But you must look. He had cycled every night, sometimes twice a night, in a big figure of eight from Walton-on-Thames to Hampton Court Bridge looking for that car, looking for a murderer. And in the end he had found him. And in doing so he had found himself.