There was a pause before the rider replied in a deep voice that carried the length of the wall on each side of the gate. ‘I am King Caratacus, warlord of the free tribes of Britannia.’

Cato felt his blood chill. He leaned forward across the rail the better to make out the rider. In the torchlight the man’s face was clear enough to prove the truth of his words.

‘I have come to claim back what is mine,’ he continued clearly in fluent Latin. ‘You have my brother. I command you to give him up to me, if he still lives.’

Cato’s mind was racing with surprise and the implications for the wider campaign now that the enemy leader was before him. If Caratacus had word of his brother’s capture and rushed south to negotiate his release then the enemy army was without its commander. It presented a fine opportunity for Governor Ostorius to strike. The ladder creaked and a moment later Macro climbed on to the platform, breathing heavily from his exertions.

‘You heard?’ Cato asked him.

‘Yes. Bastard has a fine pair of lungs on him. Doubt there’s a man in the fort who doesn’t know he’s right on our doorstep.’ Macro glanced over the breastwork and shook his head admiringly. ‘Whatever else you say about him, the lad’s got balls.’

‘We should kill him. Now,’ Quertus growled. ‘Before the fool rides away.’

Macro sucked his teeth. ‘He’s right. Kill him.’

‘No,’ Cato replied decisively.

The enemy commander called up to them again. ‘I asked if you had my brother, Maridius. Centurion Quertus, speak up and answer me!’

Before the Thracian could respond, Cato leaned forward. ‘I am in command at Bruccium. Prefect of the Thracian Cohort.’

‘Prefect? What happened to that vile cur Quertus?’

Cato answered as loudly as he could, so that the garrison would hear him. ‘He serves me now.’

‘And who are you, Roman? What is your name?’

There seemed no advantage to be gained from not answering and Cato drew a deep breath. ‘Prefect Quintus Licinius Cato.’

‘Prefect Cato . . .’ There was a brief pause. ‘Is my brother alive?’

‘He is.’

‘Good. Then I demand his release.’

‘Demand?’ Macro gave a light, dry laugh. ‘The cheeky sod. Tell him to fuck off, sir.’

‘Kill him,’ Quertus muttered. ‘Before it’s too late.’

Cato ignored them both. ‘Maridius is my prisoner. Why should I release him?’