Strike dressed in the bathroom then moved quietly back into the dimly lit hall, where he stowed his shaving things in the holdall he had packed for Barrow-in-Furness. A door stood ajar to his right. On a whim, he pushed it wider.

The little girl whom he had never met slept here when not at her father’s. The pink and white room was immaculate, with a ceiling mural of fairies around the cornice. Barbies sat in a neat line on a shelf, their smiles vacant, their pointy breasts covered in a rainbow of gaudy dresses. A fake-fur rug with a polar bear’s head lay on the floor beside a tiny white four-poster.

Strike knew hardly any little girls. He had two godsons, neither of whom he had particularly wanted, and three nephews. His oldest friend back in Cornwall had daughters, but Strike had virtually nothing to do with them; they rushed past him in a blur of ponytails and casual waves: “Hi Uncle Corm, bye Uncle Corm.” He had grown up, of course, with a sister, although Lucy had never been indulged with sugar-pink-canopied four-posters, much as she might have wanted them.

Brittany Brockbank had had a cuddly lion. It came back to him suddenly, out of nowhere, looking at the polar bear on the floor: a cuddly lion with a comical face. She had dressed it in a pink tutu and it had been lying on the sofa when her stepfather came running at Strike, a broken beer bottle in his hand.

Strike turned back to the hall, feeling in his pocket. He always carried a notebook and pen on him. He scribbled a brief note to Elin, alluding to the best part of the previous night, and left it on the hall table so as not to risk waking her. Then, as quietly as he had done everything else, he hoisted his holdall onto his shoulder and let himself out of the flat. He was meeting Robin at West Ealing station at eight.

The last traces of mist were lifting from Hastings Road when Robin left her house, flustered and heavy-eyed, a carrier bag of food in one hand and a holdall full of clean clothes in the other. She unlocked the rear of the old gray Land Rover, swung the clothes into it and hurried around to the driver’s seat with the food.

Matthew had just tried to hug her in the hall and she had forcibly resisted, two hands on his smooth warm chest, pushing him away, shouting at him to get off. He had been wearing only boxer shorts. Now she was afraid that he might be struggling into some clothes, ready to give chase. She slammed the car door and dragged on her seatbelt, eager to be gone, but as she turned the key in the ignition Matthew burst out of the house, barefoot, in T-shirt and tracksuit bottoms. She had never seen his expression so naked, so vulnerable.

“Robin,” he called as she stepped on the accelerator and pulled away from the curb. “I love you. I love you!”