“Right you are, miss,” he said and shut the door firmly behind us. We rode down in the lift in silence. As we stepped out into the bright foyer an idea struck me. “I’ve just thought of something,” I said. “If Mrs. Preston isn’t working here at the moment, she’d have free time, wouldn’t she? And I’m moving into a little mews cottage just off Knightsbridge. I’m desperate for someone to come and clean the place for me and she’d be perfect, wouldn’t she?”

“I expect she would, miss,” he said.

“So do you happen to have her address?” I asked. “I’ll go and see her right away.”

“It’s here somewhere.” He went into his cubby and rummaged around, producing a stack of calling cards and papers. “Hold on. Just a minute. Here we are.” He produced a grubby index card. “It’s 28 Cambridge Mansions, Cambridge Street.”

“Oh dear, where would that be, do you know?”

“Just behind Victoria Station, I believe. Not too far from here because she had to walk the last time we had a pea-souper fog and the buses weren’t running.”

I took out the small notebook from my purse and copied down the address. “Thank you, Frederick. You have been most helpful. But I’m so worried about dear Bobo. I wonder if any of her other friends would know more about what happened to her? Whom do you think I could ask? I’ve been living at home in the country so I’m completely out of touch with her friends these days.”

“I couldn’t say, miss.” His face was expressionless. “Not many friends come to visit here. At least not when I’m on duty.”

Was he hinting that most of Bobo’s friends came after dark?

“Perhaps someone at Gussie Gormsley’s tonight will know more,” I said. “Thank you again.”

And out I went into the fog. In a way it had been a frustrating visit. I hadn’t learned any more about Bobo—or had I? One thing was obvious: she lived in a very expensive flat in the most expensive part of London. But her jewelry was flashy and paste, not real. She had no job and apparently no family. So how could she afford to live there? I’d have to find out from Sir Jeremy this afternoon who was paying the rent on that flat, and whether the person (presumably male) who paid the rent was also paying the doorman to keep silent.