‘Wait!’ Cato commanded. ‘Compose yourself! You’re a bloody officer.’ He turned to Macro. ‘Stay here. Have the men drop their packs and prepare to fight. Do it as quietly as you can. The decurion and I are riding ahead to see what’s going on.’

‘We are?’ Trebellius looked shocked. Then, as Cato glared at him, the decurion fought to steady his nerves and nodded. ‘Yes, sir.’

‘Then let’s go.’ Cato spurred his mount into a canter. After a moment’s hesitation the decurion followed and Macro turned towards the squadron and Decimus and drew a deep breath to bellow his orders. Then he caught himself and spoke in a husky undertone. ‘Now then, lads, let’s do this without too much noise, eh? Packs down . . .’

As the track began to bend round the foot of the cliff, Cato slowed his horse to a trot and then stopped. The sound of the horn was clearer now, and he could hear men shouting. He glanced at the cliff and saw that it was less than fifty feet in height at this point. Some rocks had fallen by the side of the road and it should be possible to climb to the top.

‘Take my horse,’ Cato ordered as he slipped from the saddle and began to scramble over the rocks and up the cliff.

The decurion watched his superior in alarm. ‘Where are you going, sir?’

‘To spy out the lie of the land.’ Cato paused and looked down over his shoulder. ‘Just make sure you stay there.’

He did not wait for a reply but continued up, carefully testing his grip on the handholds and the weight on his boots as he made his way towards the top. It was a short climb but he was breathing heavily as he hauled himself over the crumbling edge and slithered far enough away from it to be sure it would not give way beneath him. Then, rising cautiously to his feet, he looked in the direction of the horn as it sounded again. On the far side of the cliff the track continued straight down the valley, towards a small hillock on top of which sat a Roman outpost. Around it, in a loose circle, were a hundred or so figures armed with shields and spears. A handful wore helmets but the rest were bareheaded with long dark hair tied back. As Cato watched, some more emerged from the trees a short distance away, carrying a stout length of timber. They made directly for the fort and their intention was perfectly clear. Cato made sure that there were no more of the enemy visible before he climbed back down to Trebellius and took his reins and swung himself back into the saddle.

‘The enemy are attacking the outpost. There’s no time to lose if we’re to save them!’