"And you yourself put it in, locked the door, and have retained the key ever since?" Malcolm Sage had exhausted the interest of the sphinx and was now drawing diagrams with his forefinger upon the morocco surface of the table.
Sir Lyster nodded.
"I put the key in the pocket of my evening vest when I changed," he said. "After the other guests had retired, the Prime Minister raised a point that necessitated reference to the document itself. It was then I discovered the substitution."
"But for that circumstance the safe would not have been opened until when?" queried Malcolm Sage.
"Late to-night, when I should have transferred the packet to the safe in my dressing-room."
"Would you have examined the contents?"
"No. It is my rule to cut adrift from official matters from dinner-time on Saturday until after breakfast on Monday. It was only in deference to the Prime Minister's particular wish that we referred to the document to-night."
"I take it that the rule you mention is known to your guests and servants?"
"Certainly."
"There is no doubt that it was the document itself that you put in the safe?"