There were steel shutters on all the windows, and only tiny cracks and spears of light penetrated the rooms they walked through. Some of the furniture had been covered with dustsheets, so that mysterious shapes stood all around them in the gloom, pushed back against the walls and shrouded like corpses.

‘Are you selling the house furnished?’ asked Cooper, stumbling against the corner of what felt like a dining table.

‘This is a little different from the normal house sale,’ said Casey. ‘Some of these items have great historic value in the right context.’

‘You mean they belong here and nowhere else?’

‘I suppose you could put it that way. The vendors were concerned that some of the rooms should stay intact, if possible. Of course, it raised the price a little.’

‘Most people like to stamp their own personality on a place when they move in,’ said Cooper. ‘They want to change everything.’

‘Not here.’

John Casey stopped in front of a door. It might have led to a boiler room, or a furniture store – some aspect of the behind-the-scenes activities in a large house. There was no outward clue to the stone steps that were revealed when the agent produced the key from his ring and eased open the lock. The steps were deeply worn in the middle, as if many feet had passed up and down them over the centuries.

Casey went first, after finding the light switch. Cold air greeted him as he descended – the coolness characteristic of a cellar, a chill caused by being too close to the damp soil pressing against the walls.

Cooper was glad that the lights were working. He wouldn’t have welcomed walking into this room in the dark, even if he’d known what to expect. The problem was the skulls. Hundreds of them grinned from shelves and niches cut into the stone walls. Some of them had fallen apart, their jaw bones slipping and sitting at awkward angles, their teeth loosened and lying in the dust. Some had gone beyond grinning, and had deteriorated into expressions of slack-mouthed, manic laughter.

Beneath the skulls, hundreds of bones had been stacked in ragged piles. Among a jumble of tibias, fibulas and femurs, Cooper distinguished the shape of a pelvis and a few ribs. They’d been heaped together with no regard for their original ownership. Not unless the pile of bones nearest to him had belonged to a man with three legs and no hips.

‘Quite impressive, aren’t they?’ said Casey. ‘Not everybody’s cup of tea, of course.’

He reached out a hand to stroke the cranium of a large skull occupying a niche of its own near the bottom of the steps. The bony plates over its eye sockets were smooth and shiny, gleaming with a pearly luminescence in the reflected light.

‘This one is supposed to bring you luck, if you rub it,’ said Casey. ‘He’s called the General.’