“Because I told you so.”

“But you might not be speaking the truth⁠—or the watch you went by might be wrong. But Parker also says that you left the house at ten minutes to nine. So we accept that statement and pass on. At nine o’clock you run into a man⁠—and here we come to what we will call the Romance of the Mysterious Stranger⁠—just outside the Park gates. How do I know that that is so?”

“I told you so,” I began again, but Poirot interrupted me with a gesture of impatience.