Nightingale parked the Jag in a residents-only bay and we walked up Downshire Hill looking for the address. It turned out to be one of a row of grand Victorian semidetached mansions set back from the north side of the road. It was a seriously buff house with gothic trim and bay windows; the front garden was professionally cared for and judging from the absence of an intercom, the Coopertowns owned the whole thing.

As we approached the front door we heard an infant crying, the sort of thready, measured crying of a baby that was settling in for a good wail and was prepared to keep it up all day if need be. With a house this expensive I was expecting a nanny or, at the very least an au pair, but the woman who opened the door looked too haggard to be either.

August Coopertown was in her late twenties, tall, blonde and Danish. We knew about the nationality because she managed to work it into the conversation almost immediately. Before the baby she’d had a slim, boyish figure, but childbirth had widened her hips and put slabs of fat on her thighs. She managed to work that into the conversation pretty quickly, as well. As far as August was concerned, all of this was the fault of the English, who had failed to live up to the high standards a well brought-up Scandinavian woman comes to expect. I don’t know why; perhaps Danish hospitals have gyms attached to their maternity units.

She entertained us in her knocked-through living room stroke dining room with blond-wood floors and more stripped pine than I really like to see outside of a sauna. Despite her best efforts, the baby had already begun to make inroads into the ruthless cleanliness of the house. A feeding bottle had rolled between the solid oak legs of the sideboard, and there was a discarded romper suit balled up on top of the Bang & Olufsen stereo. I smelled stale milk and vomit.

The baby lay in his four-hundred-quid cot and continued to cry.