Cato struggled for a response, but his mind was too tired to develop a line of reasoning to excuse himself. Instinctively he knew that Macro was right: he was thinking more about himself than the responses of the men, and he looked down guiltily. ‘Nothing . . . I can’t bear it.’

The veteran looked at him closely, a bitter expression on his face, the muscles of his cheeks tightening and twitching. For a moment Cato thought that Macro would explode and shout him down in front of all the men. The humiliating vision filled his mind to the exclusion of anything else, so profound was Cato’s fear of shame and inadequacy. Then Macro looked past Cato, aware of the faces that had turned towards the two centurions. He breathed in deeply through his nose and forced himself to release the tension that gripped his body like a vice.

‘Well, you have to bear it,’ Macro said quietly. ‘This is as bad as it gets, Cato. And you have to be calm, control yourself and not give way. Or at least, try to be as calm as you can.’ Macro shook his head sadly as he recalled his initial wave of rage when the first prisoner had been broken.

‘Is there nothing we can do about it?’

Macro shrugged. ‘What did you have in mind?’

‘I don’t know. Perhaps we might try to rush them, and get our men back.’

‘Cato, they’re dead either way. If we rescue them, what then? They’ll live a few more hours before the royal enclosure falls, that’s all. And if our rescue attempt goes wrong, we all die a bit sooner.’

‘So what difference does it make?’

‘Not much,’ admitted Macro. ‘I just know it’s our duty to guard the king, and hold out for as long as possible.’

‘And we just let them carry on with that?’ Cato pointed down the street.

‘What else can we do?’

The younger man opened and closed his mouth. Despite the waves of revulsion, despair and a need to do something, there really was nothing to be done about the situation. He was a helpless member of the audience before the horror being staged.

‘We could try to rush them,’ he said in the end.

‘No. I won’t allow it. In any case, they’d try to kill those prisoners the moment we opened the gates. That’s the end of it, Cato. The end, you hear?’

Cato nodded, and Macro patted him on the shoulder, before turning back towards the enemy. Sensitive to the need to divert Cato, he pointed towards the warriors standing round the remaining prisoners.

‘Did you notice that the only men he’s got with him are Atrebatans?’

Cato glanced round. ‘Yes . . . Smart move.’

‘Smart?’