Macro thought a moment and shook his head. ‘They’d be too exposed to the slingers. Besides, there’s too little left in the cistern to make a difference. Just pull the men back from those sections on fire. The rest can stay in place.’

Petillius saluted and hurried away to carry out Macro’s order. He stayed on the wall for a short while longer, until the pain in his lungs had passed off, and then descended into the fort and stood back by the end of the nearest barrack block. The fires had established themselves now and flames licked around the angle of the gatehouse. There was nothing that could be done to save the structure, Macro realised. It would be gradually consumed by the flames and eventually collapse. The fire would burn on for a few hours before it died down. Come the dawn, it would be a smouldering ruin, and there would be nothing to prevent Caratacus and his army from picking their way over the charred remains and falling on the waiting men of the garrison.

When Petillius returned to his side, Macro told him to leave a handful of men on watch and order the others to come down and rest between the barrack blocks.

‘And what of the horses and the men in the hospital, sir?’ Petillius asked quietly.

Macro stared at the flames for a moment before he answered. ‘We’ll deal with it at the last moment. Best not to lower the men’s spirits before then. I’ll give the order when the time comes.’

‘Yes, sir.’

‘Once you’ve seen to the men, get some rest yourself, Petillius.’

‘So should you, sir.’

Macro patted him on the shoulder. ‘I’m fine.’ He jerked his thumb towards the fires. ‘Until that lot burns out, we’re not going to be troubled. I’ll be at headquarters for a while, if anything comes up.’