“This is the service lift,” he explained. “It runs to the kitchens at the top of the building. You order through this telephone, and the dishes are sent down in the lift, one course at a time. The dirty plates and dishes are sent up in the same manner. No domestic worries, you understand, and at the same time you avoid the wearying publicity of always dining in a restaurant.”

Poirot nodded.

“Then the plates and dishes that were used tonight are on high in the kitchen. You permit that I mount there?”

“Oh, certainly, if you like! Roberts, the lift man, will take you up and introduce you; but I’m afraid you won’t find anything that’s of any use. They’re handling hundreds of plates and dishes, and they’ll be all lumped together.”

Poirot remained firm, however, and together we visited the kitchens and questioned the man who had taken the order from Flat 11.