I forbore to pander to his conceit by asking the obvious question. I knew the answer, at least I knew what Poirot’s answer would be, and instead I tried without success to elicit some information as to what steps he was taking to track down the enemy. As usual he had kept me completely in the dark as to his movements, but I gathered that he was in touch with secret service agents in India, China, and Russia, and, from his occasional bursts of self-glorification, that he was at least progressing in his favourite game of gauging his enemy’s mind.

He had abandoned his private practice almost entirely, and I know that at this time he refused some remarkably handsome fees. True, he would sometimes investigate cases which intrigued him, but he usually dropped them the moment he was convinced that they had no connection with the activities of the Big Four.

This attitude of his was remarkably profitable to our friend, Inspector Japp. Undeniably he gained much kudos for solving several problems in which his success was really due to a half-contemptuous hint from Poirot.