I stared, frowning. It appeared that she had taken a trip. But if she had known she was going away, why hadn’t she told me? Why did she agree to come with me to show Marina around London? An impromptu trip then. Maybe summoned home by a family illness? I knew she was fond of her father, but loathed her stepmother. Maybe it was simpler than that. Maybe she had met a man at Crockford’s who suggested a rendezvous in the New Forest or a few days in Paris. That sort of thing happened to Belinda. I gave a sigh of relief. I was worrying for nothing. She had gone away. She was quite all right. And wherever she had gone it was none of my business.

I came downstairs, let myself out and locked the door again. Then I set out for Mrs. Preston’s flat. I headed behind Victoria Station, down Sloane Street and across the Pimlico Road, and eventually found Cambridge Street coming off Hugh. It was a narrow little road, not nearly as grand as it sounded, and 28 Cambridge Mansions was really just a flat in a dingy building with a stone staircase that smelled of dog. I was rather out of practice for long brisk walks and had to stand on the landing catching my breath before I tapped on her door. It was opened a few inches by a woman with curlers in her hair. A small hairy dog yapped at her feet. Not a person I would immediately have chosen to clean my house if I ever owned one.

“Mrs. Preston?” I asked.

“Who wants to know?” she demanded.

“I’m a friend of Miss Carrington.” I gave her a warm smile. “Can I come in for a minute? It’s awfully cold out here.”

“If you must.” She opened the door and led me into a threadbare sitting room, which was almost as cold as the landing had been. She nodded to a chair by an unlit fire. “I always sit in the kitchen myself,” she said. “And I’m out during the day usually so there ain’t no point in wasting coke.”

She was a skinny, birdlike woman with sharp features and quick movements and she was still standing with hands on hips, watching me with suspicious dark eyes.

“I’m sorry to be barging in on you like this,” I said. “And I feel rather awkward about doing it, but I’ve been sent to collect the key to Miss Carrington’s flat. They said you still had one.”

“They don’t trust me no more?” she demanded. “Me, what’s been doing for her for years now?”

“I’m sure Miss Carrington trusts you completely,” I said hastily. “But you know what building managers are like. Always think the worst, don’t they?”

“I suppose they do, ruddy lot,” she muttered. “So she don’t want me to clean no more, is that it?”