“The Premier started for London. The car was a closed one. He and Captain Daniels sat inside. The second car followed as usual. But, unluckily, for some unknown reason, the Prime Minister’s car deviated from the main road⁠—”

“At a point where the road curves?” interrupted Poirot.

“Yes⁠—but how did you know?”

“Oh, c’est évident ! Continue!”

“For some unknown reason,” continued Lord Estair, “the Premier’s car left the main road. The police car, unaware of the deviation, continued to keep to the high road. At a short distance down the unfrequented lane, the Prime Minister’s car was suddenly held up by a band of masked men. The chauffeur⁠—”

“That brave O’Murphy!” murmured Poirot thoughtfully.