Then Cooper shook his head. No, not a graveyard. That wasn’t right. There had been no attempt at burial here, only prolonged exposure of the corpse to the air, a sacrifice to the destructive effects of the Peak District climate. This building couldn’t be considered a graveyard. But it might be called a charnel house. A dead place.

Near the skull lay a large stone, which he’d dislodged when he fell. Cooper remembered the stone on the hillside at Ravensdale. The grass had been pale green underneath it, recently covered over. But the underside of this stone and the ground it had been lying on were swarming with wood lice. Their grey shapes scurried in all directions when he turned it over.

As a child, Cooper had known the tiny crustaceans as coffin cutters. He imagined the name must have originated in one of those rural beliefs around death. Wood lice liked the dark and the damp, they were associated with dead and rotting vegetation. They were like flat little tanks, with legs that protruded from overlapping armoured plates. But he’d been told that the reason wood lice sought the dark and damp was because their bodies weren’t watertight. They dried up and died when they were exposed to the air.

Straightening up, Cooper backed away from the skeleton towards the wall. With some difficulty, he located a couple of toe holds where the crumbling mortar had left gaps between the limestone blocks. Stone dust and fragments of mortar cascaded down the wall, dislodged by his boots. He winced, hoping he wasn’t doing too much damage to the scene. He’d never hear the end of it, if he was.

Finally he saw the tree branch close above his head and was able to reach it to help himself up to the top of the wall. He scrambled over the edge and slid back down into the undergrowth. Beyond the woods, he could hear the occasional sound of an engine. For a moment, one of them seemed very close, but it stopped and he wasn’t sure. Distances could be very deceptive.

Cooper took a few steps away from the building into the overgrown weeds, intending to wait under the trees. But before he’d gone three yards, he felt something give way beneath his foot with a metallic snap. For a split second, he felt only the instinctive fear of an unseen danger. There was no time for his muscles to respond.

Then steel jaws slammed shut on his ankle, biting hard from both sides, their teeth sinking in deep. He staggered, thrown off balance by the sudden loss of use of his right foot. Then the impact was followed by pain, and he could feel the jaws gnawing deeper with the slightest movement. Driven by its powerful spring, the trap had caught him just above the top of his boot, penetrating his trousers and socks and puncturing the soft flesh with vicious ease.

Cooper collapsed in the grass, gasping at the jolt of agony as the metal teeth moved sideways, tearing at him like the blades of a saw. He fumbled desperately at his foot, found the jaws of the trap and felt the rusted metal, already slick with his blood. It was an old-fashioned animal trap, shaped like a clamshell and sprung by his weight on a strip of steel lying in the grass.