Every entry, going back three years, plus my assistant’s, plus the visitor log from the office, plus — and this is the request that told me she already knew what she was looking for — a list of every occasion in three years on which somebody had come to the house rather than the office.

Nine days later she put fourteen pages in front of me with a single-page summary on top, and the summary had a sentence in it that I have never forgotten.

She said: “I can’t tell you what anybody knew.

I can tell you that on six occasions in nineteen months, a competitor moved within seventy-two hours of a meeting that took place inside your house and nowhere else.”

Six for six.