Here, as with everything else, the precision was absolute, timetables agreed and adjusted weeks in advance to fit parents’ requirements, and usually the convenience of private aircraft. Azziz’s departure was scheduled for noon. His father had brought the Scheherazade into harbour at Monte Carlo and the Alouette helicopter, which had its own pad and hangar at the stem, could make the journey to Zurich and back to the yacht in under four hours, with the inconvenience of road travel only necessary from the school to the airport. The school’s closeness to the tight-packed foothills prevented its having a landing pad of its own.

Azziz’s car left the school grounds at eleven. All three bodyguards were with him. The American, Williams, who had been a Green Beret officer and then a contract employee for two years with the CIA, rode in the back alongside the boy. One Bedouin drove, the other sat beside him in the front; from their clothes and demeanour it was difficult to tell that they were Arabs, or had, ten years earlier, been desert tribesmen.

Obediently the driver kept to the speed limit crossing the ancient bridge, only accelerating slightly along the winding driveway through the outer grounds beyond; to the left were the playing fields, skating rink and covered swimming pool. The gateman was waiting at the boundary wall. He looked in, smiled and then operated the electrically controlled outer protections.

The car turned right, onto the main road, almost immediately picking up the river Limmat; from the hills it was possible to see the lake into which it fed.

“Looking forward to the vacation?” asked Williams. With the boy safely aboard the yacht, he would have two clear months to himself. His sister was expecting him in Houston by the end of the week.

“Very much,” said Azziz. He hadn’t found it easy, achieving the examination grades. But he had managed. He knew his father would be pleased. It was important always to please his father.