Behind the caravan, a row of silage bags glistened in black plastic wrappings, pools of water reflecting the branches of the trees. Overhead, the upper boughs were full of dark, untidy shapes – the nest of the rooks Cooper could see flapping restlessly against the sky.

‘Just that some people prefer not to get visitors . . .’ he said.

‘Oh, I feel that way myself some days.’

‘. . . and it usually means they have something to hide.’

Finney sniffed sceptically, but trailed after Cooper as he approached the trees. The nearer he came to the caravan, the more Cooper became aware of the silence in this corner of the field. Apart from the rustling of the birds, there was no sound or movement, no sign of life. Surely someone who didn’t like visitors would be alert for a stranger approaching, or the sound of a car parking in the lane.

Cooper stopped and looked around. The field was full of tussocky grass and outcrops of flat, pale limestone. It was enclosed by two walls that snaked across the landscape until they crested a rise. Halfway up the slope, a section of wall had bulged and fallen. The dislodged stones lay on the ground, grass growing over them. This land hadn’t been used to contain livestock for a while – not unless Mr Finney was happy for his animals to scramble over the damaged wall.

‘I don’t suppose Mr Nichols has a car, sir?’

‘A car? No. I give him a lift into town now and then, if he needs to go to the doctor’s or something,’ said Finney. ‘Otherwise, he gets around on that –’

The farmer pointed to an old motorbike propped against one end of the caravan. Cooper hadn’t noticed it until now. It was so decrepit that it seemed to have grown out of the weeds.

‘He uses the bike to get around? Even when he’s out drinking?’

‘Sometimes.’

‘But he isn’t out on it now, is he?’

‘I reckon not.’

With a sinking feeling, Cooper knocked on the door of the caravan. ‘Mr Nichols? Are you in there?’ He knocked again, a metallic clanging as if he was hitting a big tin can. A big, empty tin can. ‘Anyone home?’

‘He might be asleep,’ said Finney.

Faded curtains were drawn across the windows. A pattern of orange flowers, speckled with black dots. By pressing his face close to the glass, Cooper could see a small slice of the interior through a narrow gap where the curtains didn’t meet. He saw the edge of a folding wooden table, a scatter of papers, and two beer cans. Orange cans, to match the curtains. Probably Stone’s Bitter from the supermarket in Matlock. One of the cans had been knocked over, and beer was spilt on the table.