The professor himself was easily recognizable in the photo, though he was ten or fifteen years younger and dressed to the nines in a dinner suit and red bow tie, with a matching handkerchief in his top pocket. The lady with him was tall and elegant, and equally well dressed in a red gown that exposed smooth, white shoulders. The couple stood close together as they posed for the photographer. Their manner didn’t seem artificial – they looked genuinely happy and affectionate.

Robertson moved over to the cabinet and bent to look at the photo as if he’d never seen it before.

‘Yes, that’s Lena. We were attending some academic bunfight somewhere.’

Cooper wasn’t quite sure how to ask the next question. ‘Is she …?’

The professor watched him for a moment, almost seeming to enjoy his discomfort.

‘Lena died five years ago, shortly before I retired.’

‘I’m sorry.’

‘It was cancer, of course.’

‘Of course?’

‘Cancer is rather like the ancient mariner, isn’t it? You remember the Samuel Coleridge poem? “It is an ancient Mariner, And he stoppeth one of three.”’

‘I’m sorry,’ said Cooper. ‘I don’t –’

‘One in three people in this country suffer from cancer at some time in their lives.’

‘Ah.’

Robertson turned away from the cabinet and walked to the window. He gazed out at the new houses in the crescent below him. Cooper caught that faint smell again. It made him think of mothballs, too. But he didn’t know what mothballs smelled like, or even if they were used any more. He associated them with grannies and antimacassars. He’d have to call in Boots the Chemists and ask for some, to see if he could put a name to the smell. Otherwise, it would remain permanently elusive.

Finally, the professor stopped moving and turned to face him. ‘Modern society has mismanaged death, don’t you think? Most people would say they want a quiet, dignified death. Yet the majority of us die in hospitals, surrounded by respirators, dialysis machines, naso-gastric tubes, undergoing endless sessions of chemotherapy and cardio-pulmonary resuscitation procedures. Death is converted into a mechanical spectacle, the weapons of technology lined up against the processes of nature. A miniature Armageddon fought in the veins.’

‘It must have been a very difficult time,’ said Cooper. It was a phrase he’d heard people say in these circumstances. He’d never thought it meant very much. And it didn’t now, when he said it himself.

‘My wife taught me that there are two stages of dying to go through,’ said Robertson. ‘First, you’re afraid that you’ll die. And then you’re afraid that you won’t. There’s a point when death becomes a thing to be welcomed, the event you desire most in the world. Some of us reach that point before others.’

Cooper began to button his coat. He knew when it was time to leave.