Forrester had gone very pale. ‘You don’t think they are wearing this skin? That Cloncurry is driving around in this guy’s fucking skin?’

‘It’s very possible. That’s what the Aztecs would do. Wear the human skin of their victims, like a suit, until it literally rotted away from them. The stench must have been appalling.’

‘We certainly haven’t found the skin yet. We’ve called in the dog unit.’

‘That’s a good idea. I consider it entirely possible they are wearing the skin. As they are following the Aztec method so closely.’

They both fell silent once more. De Savary gazed across the rolling parkland, the lofty trees bending over the river; the beautiful scene of tranquil, bucolic Englishness. It was hard to reconcile with that…that thing suspended on a wooden frame, just yards away. The pink and inverted cadaver; with its hideous grin of pain.

The detective stood up. ‘So what were they looking for? The gang. I’ve been searching. There’s no connection with the Hellfire Club at all.’

‘No.’ said De Savary. ‘But there is a curious connection between this school and the Middle East.’

‘And that is what?’

De Savary smiled, very hesitantly.

‘If I recall from what I read on the train, the tuck shop should be down here.’ He strode around the front of the building, Forrester following. At the far end of the south wing there was a curious gabled building adjoining the main elevation. It looked like a chapel. De Savary stopped.

Forrester gazed at the red-and-black design of the impressive doors: a motif of winged metal lions. ‘What’s that?’

‘This is the Nineveh Porch. It has a profound association with Iraq and Sumeria. Shall we see if our guys were down this end?

Forrester nodded.

De Savary prodded the metal door and it swung open easily. Inside, apart from some peculiar stained glass windows, it looked like a normal tuckshop for a rich school. There was a Pepsi machine. A till. And boxes of snacks and crisps chaotically scattered on the floor. But the boxes were scattered too randomly. The unlit room had been ransacked. On closer examination, the wooden panelling along one wall had been ripped away; a window was broken. Someone had been in here, vigorously searching for something. Whether they had taken anything was a different matter. De Savary guessed they hadn’t. The scattering of items in the tuck shop looked angry: frustrated and thwarted.

They stepped out into the peaceful sunshine and walked along the pathway. Pollen drifted languidly on the mild sunny air as De Savary told the tale of the Nineveh Porch. ‘The porch was ordered by Lady Charlotte Guest and her husband Sir John around 1850. It was built after a design by the architect Charles Barry, better known as the creator of-’

‘The Houses of Parliament,’ said Forrester. And he smiled shyly. ‘Architecture is a private hobby.’

‘Quite so! The Houses of Parliament. Anyway the Nineveh Porch was a private loggia, built expressly for the purpose of housing some famous Assyrian reliefs gathered from Victorian explorations of Mesopotamia. Hence the rather unusual doors, with the Assyrian lions.’

‘Right.’

‘These reliefs, housed in the porch, had been excavated by Austen Henry Layard, a cousin of Lady Charlotte Guest. The reliefs were significant and substantial. Each weighed several tons. They had originally adorned important thresholds in Nimrud.’

‘And Layard and Barry put them here?’

‘Yes. And together with a number of other reliefs they remained here, in the Nineveh Porch, until shortly after the First World War. Then the whole collection was offered for sale.’

‘So there’s nothing left?’

‘Hold on! The antiquities in the porch were replaced by humble casts. In 1923 Canford Hall itself was sold by the Guest family and it became a boys’ school. At that point, the Nineveh Porch, now robbed of its ancient treasures, was turned into a tuck shop. Selling sandwiches and Snickers bars.’

‘So our guys must have known this? That nothing was left. Why come here again?’

‘There is a slightly odd denouement to the story. In 1992 two academics came here. Both experts in Assyriology. They were on their way to a conference in Bournemouth but they had some time, so they decided to make a quick pilgrimage to this place so important in their discipline. They didn’t expect to find anything. But they looked at the stained glass windows, with their pictures of Sumeria, and they admired the vaguely Assyrian detailing of the architecture. And then they looked behind the Pepsi machine-and they found an original relief.’

‘You’re joking.’

‘No. Only the casts were supposed to be left. But lo and behold! One more piece remained. It was recognized as the real thing, although covered by layers of white vinyl emulsion. The relief was taken down and sent to London, where it was offered for sale at auction by Christie’s. It was bought by a Japanese dealer, apparently acting on behalf of a religious sect. The price was, I think, around eight million pounds. The highest amount ever paid for an antiquity anywhere in the world. Et voilà.’

They had reached the riverbank. The rushing River Stour was before them; sunlight dappled across the waters, spangled by the arch of leaves above.

‘I still don’t get it,’ said Forrester. He picked up a stick and threw it into the river. ‘What links this with the Hellfire stuff?’

‘You remember what I told you on the phone the other day?’

‘About the Yezidi and the Black Book? How that might be what they are seeking?

‘Precisely. Austen Henry Layard, you see, was one of the first ever westerners to meet the Yezidi, in 1847. He was excavating in northern Iraq, in Ur and Nineveh. The early years of modern archaeology. Then he heard about this strange sect that lived near Mosul, around Dahuk. Layard made contact with the Yezidi. Then he was invited to their sacred capital Lalesh. In the mountains. It’s a dangerous place, hostile to this day.’

‘What did he do there?’

‘Now that’s a question. We know he was invited to witness some of their most secret ceremonies. A privilege, as far as I know, afforded to no one else before or since.’

‘Did they give him the Black Book?

De Savary smiled. ‘Detective! First rate work. Yes, that’s one theory. Scholars have speculated that Layard must have had a very close relationship with the Yezidi, to be treated the way he was. Some think he may have taken the Black Book with him. Thus giving rise to their legends that it came to England.’

‘So, if he had brought it back he might have brought it here, to the building designed for the best antiquities, the ones he kept to himself? Right?’

‘Vraiment!’

Forrester frowned. ‘But I thought we established that Jerusalem Whaley already had the Black Book. How does Layard get involved?’

De Savary shrugged. ‘Who knows? Maybe Jerusalem Whaley thought he had the Book, but didn’t. Maybe he gave the Book back to the Yezidi and Layard went to get it again, a century later. Shuttling back and forth! My personal hunch, for what it is worth, is that Jerusalem Whaley had the Book all along, and Layard is just a diversion.’

‘But the main thing is we can assume that this is what the gang are after. Otherwise they wouldn’t have come here. So it’s not necessarily anything to do with the Hellfire Club in itself. The gang are actually after the Black Book of the Yezidi. That’s their real prize.’

‘Yes.’

Forrester whistled, almost cheerfully. He slapped De Savary on the back. ‘Thanks for coming, Hugo.’

De Savary smiled, though he felt guilty for doing so. The smell of the man’s exposed flesh had not quite left his nostrils.

A loud shout ripped through the silent wood.

‘Angus! Angus!’

Something was up. Another shout echoed across the parkland. The shout was coming nearer.

De Savary and Forrester scrambled up the rise. A constable was running across the lawns, chasing something. Shouting out the name Angus.