A towering man in a gown moved among the visitors, nodding and smiling at nobody in particular with his hands behind his back, like royalty inspecting Third World troops. I had seen him before – the impossibly tall man at the funeral of Hugo Buck.

‘That’s the Head Master,’ Mallory said. ‘He’s expecting us.’

Peregrine Waugh, Head Master of Potter’s Field College, stood at the window of his study and stared across the playing fields.

‘Three Prime Ministers, twelve Victoria Crosses and four Nobel Prizes,’ he said. ‘Two in physiology and two in physics. Fifteen Olympic medallists, forty-four Members of Parliament and six BAFTAs. Our drama department has always been very active. The boys were treading the boards, as it were, long before the first Old Etonian was admitted to RADA.’

‘And two murders,’ I said.

He stared at me over his rimless glasses.

‘What’s that?’ he barked.

‘Hugo Buck and Adam Jones,’ Mallory said. ‘They were Potter’s Field old boys too.’

‘Yes, yes. A terrible tragedy. Both of them. Did you arrest anyone yet?’

‘Not yet,’ Mallory said.

Waugh returned to his desk with a release of breath that might have been a sigh.

‘Although Jones left the school under a cloud,’ he said. ‘And they are not the first old boys to be murdered, sadly. Persian chap in the seventies. Filthy rich. Oil money. Mistress clobbered him with an empty bottle of Bollinger on The Bishops Avenue.’ He offered us a thin smile. ‘Privilege is no guarantee of a happy life, or even a long one. And we do know we’re privileged at Potter’s Field, gentlemen. But we give something back, you know – it’s part of the Potter’s Field tradition. Part of our ethos. Always has been. Remembrance Day service. A carol concert for the people of the town. We pay for a street cleaner. Potter’s Field Lawn Tennis Club uses our courts. And the school’s facilities – the playing fields, the swimming pool – are used extensively by local schools and various charities.’

He rose from his chair and returned to the window.

‘In fact, I think – ah yes.’ He looked at us with a delighted smile. ‘Look.’

We joined him at the window, the great green playing fields of Potter’s Field spread out before us. They were deserted apart from three figures who hovered by the touchline of the nearest rugby field. There was a man in a wheelchair, another with a walking stick, and a third, their physiotherapist, was demonstrating a stretching exercise. They all wore T-shirts. The physio’s face looked somehow unnatural, as if he were wearing some kind of mask.