‘I was in a very precarious position at Eton,’ said Haight. ‘With the death of Sir Cathal Goodenough everything changed. It was no longer a game. I couldn’t risk being found out. And when I talked to you, I realised that you already knew more than I had feared.’

‘So you gave me drugged water,’ said James, ‘with some kind of sleeping draught in it. That’s what caused the bitter, salty taste, not a water-purifying tablet. You drugged me, and told me to climb the tower…’

‘It should have been straightforward,’ said Haight. ‘A boy with heatstroke tragically slips to his death.’

‘But you hadn’t counted on Mister Cooper-ffrench turning up, had you?’ said James. ‘He saw you and tried to warn me. So, instead of pushing me off, you grabbed me and pretended you’d stopped me from falling. He saved my life. But you would have tried again, wouldn’t you? If you hadn’t found out about Victor and his paintings. Your greed got the better of you.’

‘You know,’ said Haight, ‘a lively and enquiring mind is not something to be encouraged in a boy. You shouldn’t ask too many questions.’

‘What’ll you do, sir?’ said James. ‘Put me in detention?’

Haight placed a foot on James’s throat. ‘All I have to do,’ he said, ‘is press my foot down and you’d be dead within two minutes. I could do it. I could do it as easily as stepping on an insect.’

He took his foot away and James coughed painfully. He peered up at Haight. ‘You weren’t always like this,’ he said. ‘I saw you with Mark Goodenough that day. You felt sorry for him. You wanted to help him. How could you change so quickly?’

‘I had to,’ said Haight fiercely. ‘I had to be more like my heroes. The ancient Romans were utterly ruthless. They cared nothing for their enemies. When they defeated Carthage they killed every man, woman and child, and all their animals, even the dogs, and then they ploughed the city into the ground and sowed it with salt so that nothing would ever grow there again. The only things that mattered to them were power and glory.’

‘It must be pretty glorious,’ said James, ‘murdering schoolteachers and torturing children. I’m sure you’ll be in all the history books.’

‘We’ll see, James,’ said Haight coldly. ‘We’ll see how cocky you are in the morning.’

‘Just go away,’ said James, and then added, with as much poison as he could, ‘sir…’

Haight grunted and straightened up. Then he said goodnight to the guard and James heard him splashing away past the dying oak trees.