James listened as Haight told a bloody history of invasions and warfare, and of how the Sardinians were forced inland, up into the mountains, where they lived a remote life of banditry and feuding. And he talked of the mysterious ancient civilisation that had existed on the island thousands of years ago and left behind extraordinary stone monuments, known as Nuraghi.

James wasn’t very good at sitting still and as Haight talked he looked around the room. It had been the custom for boys to carve their names here when they left the school and every inch was covered in writing. The wood panelling on the walls, the benches, the upright desks, even the block at one end that the Head Master used to flog boys on had been scratched and chiselled over the centuries. There were hundreds and hundreds of names, with more recent additions overlaying the older carvings.

James had spotted the names of two prime ministers, Pitt and Walpole, the poet Shelley and, on one panel, at least twenty-eight members of the Gosling family.

Sitting along one wall beneath a row of marble busts were some beaks. They were sticking together, nodding their heads and smoking. James cast a casual glance over them and recognised the beetroot face of John Cooper-ffrench, the classics master who Charmian had teased on the Fourth of June. He was wearing a faded tweed jacket and a striped tie and sat with his arms folded across his chest.

James marvelled at how it was that once you’d met someone you’d never seen before you suddenly saw them everywhere.

When the lecture ended Pritpal dashed off to finish his work, and Haight came over to where James and Perry were chatting.

‘Have you heard?’ he said, clapping Perry on the shoulder. ‘There’s been another burglary.’

‘M-more art stolen?’ said Perry. ‘Where from this time?’

‘Tatsmere House. Belongs to the family of a dry bob I coach, Nicholas Cresswel. I don’t think you know him. He told me on the way here this evening. Quite a haul, I’m afraid. Two Gainsboroughs, a Titian and a Canova.’

‘Do you think it m-might be one gang doing it all, sir?’ asked Perry. ‘A gang of m-murderous art thieves.’

‘That might very well be the case,’ said Haight. ‘Though, luckily, so far they haven’t murdered anyone, of course. You must tell all your friends to be on the lookout. None of these great houses that your families own are terribly secure. You must be en garde!’ So saying, Haight struck a dramatic pose with an imaginary sword and managed to crash into Cooper-ffrench, who was hurrying out of the room.

As the two men collided Cooper-ffrench was nearly knocked off his feet. Haight gabbled an apology and Cooper-ffrench tutted irritably and mumbled something about clumsiness.

James glimpsed a flash of silver and looked down to see a thin bracelet on the floor.

‘What’s this?’ he said, picking it up. He turned it in his hand. With a start of surprise he saw the letters MM inscribed on it.