‘Scraped my hand, that’s all. A week off work. Here, take this other torch, sir, while I tie my hand up. Don’t shine it. He’s in one of the side passages.’ For a long time the sound of the shot went on reverberating: when the last echo died a whistle blew ahead of them, and Martins’ companion blew an answer.

Martins said, ‘It’s an odd thing – I don’t even know your name.’

‘Bates, sir.’ He gave a low laugh in the darkness. ‘This isn’t my usual beat. Do you know the Horseshoe, sir?’

‘Yes.’

‘And the Duke of Grafton?’

‘Yes.’

‘Well, it takes a lot to make a world.’

Martins said, ‘Let me come in front. I don’t think he’ll shoot at me, and I want to talk to him.’

‘I had orders to look after you, sir. Careful.’

‘That’s all right.’ He edged round Bates, plunging a foot deeper in the stream as he went. When he was in front he called out, ‘Harry,’ and the name sent up an echo, ‘Harry, Harry, Harry!’ that travelled down the stream and woke a whole chorus of whistles in the darkness. He called again, ‘Harry. Come out. It’s no use.’

A voice startlingly close made them hug the wall. ‘Is that you, old man?’ it called. ‘What do you want me to do?’

‘Come out. And put your hands above your head.’

‘I haven’t a torch, old man. I can’t see a thing.’

‘Be careful, sir,’ Bates said.

‘Get flat against the wall. He won’t shoot at me,’ Martins said. He called, ‘Harry, I’m going to shine the torch. Play fair and come out. You haven’t got a chance.’ He flashed the torch on, and twenty feet away, at the edge of the light and the water, Harry stepped into view. ‘Hands above the head, Harry.’ Harry raised his hand and fired. The shot ricocheted against the wall a foot from Martins’ head, and he heard Bates cry out. At the same moment a searchlight from fifty yards away lit the whole channel, caught Harry in its beams, then Martins, then the staring eyes of Bates slumped at the water’s edge with the sewage washing to his waist. An empty cigarette carton wedged into his armpit and stayed. My party had reached the scene.