And so, in order to combat the terror that was eating him from the inside, he refused to allow himself to use the river as an excuse. He had made an appointment in the usual way with Dr Marie-Thérèse Calvet, flattering her in e-mail and stressing her importance to the reputation of his e-zine: Your work on the manipulation of memory using deep hypnotic suggestion is unrivalled in Europe. Your 1999 study on the alteration of recollection of early sexual experience was groundbreaking. I’d be fascinated to hear about your follow-up studies. It would make a terrific special feature for our launch edition. No, it hadn’t taken much persuasion to get her to agree to be interviewed. Like all of them, she was infested with narcissism, a trait he could use as a weapon against her.

But now he had to make a success of tonight’s business. Dr Marie-Thérèse Calvet had wanted to meet in a restaurant, perhaps because she was reluctant to allow a strange man into the privacy of her home, or perhaps because she just wanted to screw a free meal out of him, he thought cynically. They had compromised with an agreement to conduct the interview in her office at the university, thanks to his argument that she might want to be in a position to refer to her research materials. It wasn’t ideal, but at least in the evening there wouldn’t be many people around to notice him.

The one thing he was worried about was the water supply. The chances were that Dr Calvet wouldn’t have a sink in her office. And he couldn’t really wander through a university department with buckets of water. He knew from experience, however, that it took remarkably little to drown his victims. So he had packed four one-and-a-half-litre bottles of Spa in his holdall. It made it heavy to carry, but years of hard physical labour had made him strong. And he’d asked Dr Calvet about parking. She’d told him that at that time in the evening, he could easily park on either of the streets that flanked the Psychology Institute. It shouldn’t be too arduous.