‘On balance,’ said Owen, ‘I think carbon monoxide is probably the best. It takes only a few minutes. I’ve seen men still sitting in the driving seats of their cars after the exhaust has done its job. They seem just to have fallen asleep. A paramedic once told me that your blood turns cherry-red from the carbon monoxide, when it works properly,’ said Owen. ‘Your brain swells, and so does your liver and kidneys and spleen. Even the tiny blood vessels in your eyes haemorrhage. But that’s internal damage, the things you can’t see. At Suicide Corner, you always think they’re asleep at first. Until you notice the smell of the urine soaked into the cloth of the driving seat.’

Mark shifted his feet uneasily. Now he wanted Owen to stop talking.

‘This paramedic said the carbon monoxide replaces the oxygen in your blood,’ said Owen. ‘You die of oxygen starvation, a sort of internal suffocation. You can’t smell or taste or see the gas; all that happens is that you begin to feel drowsy. You get a slight headache and a shortness of breath. Then your movements slow down, there’s some nausea and chest pain, perhaps a few hallucinations. We’ve all had hangovers worse than that. But this is the sort of hangover you don’t wake up from.’

‘Owen –’

‘You wouldn’t believe the mistakes that some of them make, though. They don’t seem to plan their own deaths properly. They come with lengths of hosepipe that are too short to reach through the car window. Or they arrive with nothing to seal the gap where they have to lower the window to get the pipe through. At Suicide Corner, they can sit for a long time with the wind howling through the gap in the window and blowing away the carbon monoxide as fast as it trickles into the car.’

Mark thought for a moment of the woman, Jenny Weston, who had died with her own blood choking her heart. Her death had been sudden; she had been given no time to consider, no time to reflect on what she had done with her life, for good or for evil.

‘None of it is right,’ said Mark. At least Owen lifted his head now and met his eye. Owen’s face looked tired and drawn. The wind up here was making his eyes water. There was rain coming from the east – fat clouds were bouncing over the hills, and all the weight seemed to be in the sky.

‘Owen . . .’

‘Yes, they seem just to have fallen asleep,’ said Owen. ‘But it’s not a sleep that has any comfort in it. Only nightmares.’

Mark peered at his face, seeking to understand more clearly what he was hearing in the Ranger’s words.

‘We’ll not let that happen, Owen,’ he said.