The private road continued through the estate, ascending towards the foot of a tall mountain whose wintry slopes loomed above the trees, its peak wreathed in mist. Ben passed a keeper’s cottage and a field where Highland cattle foraged for grass among the snow. Finally, the tree-lined avenue turned a bend and Ben caught sight of Charles Stuart’s Scottish residence in all its grandeur before him.

The spectacular images on the company website hadn’t quite managed to convey the scale of the place. Nor its contrived artificiality. Carved into the foot of the snowy mountain, Stuart’s castle with its ivied turrets and towers and battlements was like some Hollywood set designer’s overblown fantasy made real, a wildly romanticised vision of a historical era that only really existed in movies where kilted heroes gallantly ran around rescuing beautiful ladies with long tresses, galloping white stallions through the heather-filled glens and battling their enemies on mountaintops with rapiers and claymores while delivering their stirring lines in a voice-coached twang that was more California than Caledonia.

Except that what was happening here inside these castle walls was very genuine. Nobody was acting. And any blood spilled would be real.

Ben passed between tall gates set into a perimeter wall and entered a courtyard. He pulled up at the foot of a broad sweep of stone steps, stepped out of the Mazda and was met there by three more men with grim faces and hard eyes. The man on the left, Ben had never seen before, but he had the look about him that the security guards on the gate hadn’t. The man on the right was the killer who had fled from the scene of Jamie McGlashan’s murder.

The one in the middle was Carl Hacker. He looked a little older and a little leaner than he had in Mad Monty’s file photographs. He was wearing a suit and tie that made him look like a corporate bodyguard or a secret service agent. Ben could see the lump of the concealed pistol under the tailored line of his suit. The other two were wearing bulkier jackets that made it harder to spot the hidden weapons underneath, but they were there. Ben could almost smell them. Like he could smell their nervousness at meeting him face to face.

‘Arms out to your sides,’ Hacker said. ‘Feet apart.’

Ben allowed himself to be frisked, which Hacker did very expertly and thoroughly while his two men searched the car and examined the contents of his bag. Ben had stopped off by the shores of Loch Ardaich en route to the castle, to dismantle his weapons and fling their components and ammunition into the deep, dark water.

Hacker took Ben’s wallet and phone. Said, ‘He’s clean.’