Cato ignored him, concentrating his attention on Tullius. ‘Sir, you change your mind now and you’re dead. Stick with our plan, and we may live. That’s all the choice there is.’

Tullius bit his lip, caught in an agony of indecision. At last he nodded his assent.

‘Good!’ Macro clapped him on the shoulder, then turned to Antonius. ‘And you? Are you with us?’

‘Yes . . .but if it comes to a trial I want it understood that I was obeying your orders.’

Macro snorted. ‘Thanks for the loyal support.’

‘Loyalty?’ Antonius arched an eyebrow. ‘That’s in rather short supply at present. I just want to live. If the choice is as Cato has described it, then going along with you is simply the best bet.’

‘Fine by me,’ said Cato. ‘Nepos, take these two through to Maximius’ sleeping quarters and tie them to the bed. Gag them as well. They have to be kept silent.’

‘There’s a better way of keeping ‘em quiet,’ Macro added.

‘No, sir. That’s not necessary. Not yet.’

While Nepos dragged the two bound officers away, the rest gathered round the large desk in the centre of the tent. For a moment there was an uneasy silence before Cato cleared his throat and turned to Tullius.

‘Sir, what are your orders?’

‘Orders?’ The veteran looked confused.

‘You’re the senior officer present,’ Cato prompted.’We have to make sure the cohort is ready to defend itself. The plan, sir?’

‘The plan? Oh, yes.’ Tullius gathered his thoughts, looked over the desk for the map of the surrounding marsh that Maximius had drafted, based on reports from the patrols, and any information the local villagers had been persuaded to divulge. The sketched marks of small tracks crisscrossed the outline of the marsh. A broader line marked the main route through the marsh, leading north towards the upper reaches of the Tamesis. Tullius placed his finger on the map.

‘If Cato is right, that’s where Caratacus and his force will be coming from. There are a handful of other tracks that could be used to enter the valley, but they’re not suitable for large bodies of men. So, we’re counting on him coming down the main track. That’s where we’ll have to hold him. Build up the existing gateway and hope we can hold it.’

Antonius looked up.’Leave the fort? But that’s madness, sir. If he outnumbers us why not fight him from proper defences? It’s our best chance.’

‘No, it’s not,’ Cato interrupted. ‘Centurion Tullius is right. We have to try and hold him back, stop him breaking out of the marsh and into the valley.’

‘Why?’

‘When I escaped from his camp-’

‘His camp?’ Antonius looked astonished.’How on earth-’