Forced to compromise, Hacker had been at pains to ensure that the prisoner’s physical needs were met. He’d even been grinding up the pills from McCulloch’s medicine bottle and mixing them into his food according to the dosage on the label, which was in Italian and caused him a major headache to translate. Whether or not the diet of pills was preventing the old guy from keeling over again, Hacker couldn’t be sure. But nonetheless he worried about what would happen when the bottle ran empty. If the pills were keeping the prisoner alive and he was liable to kick the bucket without them, whatever information he might be withholding would die with him.

Stuart had played this one well, all right, Hacker thought. For all his business genius, he was being a complete fool.

Something more was needed. If physical stress wasn’t an option, then perhaps it was time to try a more subtle approach. Hacker had been sitting alone in his private quarters within the castle when the idea had come to him. He’d called his employer on his mobile to run it by him. It had been approved.

And so, a little after two-thirty that afternoon, Hacker went to pay another visit to the prisoner. From deep in the castle’s stone passageways he descended the steps to the cellars. There was a whole complex down there, great vaulted storerooms packed with all kinds of junk and antiques. Another flight of steps led down to a dingy sub-basement where Hacker unlocked four heavy padlocks securing a thick steel door that could have contained a bomb blast. He heaved it open and locked it behind him.

From there, using an electric lantern to find his way in the darkness, he descended yet another flight of steps and passed through a steel cage door to an arched stone passageway at whose bottom was the access to the dungeon itself, an iron grid trapdoor held fast by a massive bolt. It was dank and airless down here, making even Hacker feel claustrophobic. The thought of being kept prisoner in such a place was as bone-chilling as the dampness. He slid back the bolt, set down his lantern, raised the trapdoor and lowered the ladder that was the only way in and out of the hole.

Hacker climbed down the ladder and held up his lantern, scanning around him for the prisoner but seeing only shapes and shadows. A steady drip-drip-drip of moisture leaked from the curved stone walls and echoed in the darkness. It was like entering a cave inhabited by a dangerous predator that might suddenly attack out of nowhere. Hacker drew his pistol.

‘McCulloch? Are you awake?’