“Well, you got my letter.”

“What letter?”

“My letter.”

“I didn’t get any letter.”

“Then I must have forgotten to post it. It was to tell you that I was down here tutoring your Cousin Thomas, and that it was essential that, when we met, you should treat me as a perfect stranger.”

“But why?”

“Because, if your aunt supposed that I was a pal of yours, she would naturally sack me on the spot.”

“Why?”

Bingo raised his eyebrows.