The Druids had obviously counted on the volleys of slingshot and the barricade to stop the Roman advance and had manned it with their light infantry while the remains of the heavy infantry assaulted the rear of the Roman square. The well-armoured legionaries easily cut a series of wedges into the enemy’s ranks and as more legionaries pushed through the barricade, they spread out on either side. The lightly armed Durotriges were totally outclassed. Even their reckless courage could do little to effect the outcome. Before long the leading centuries of the Roman square had formed a continuous line on the far side of the ruined barricade.

Once before, the Britons had faced the relentless killing machine of Rome, and once again they broke before it, streaming away into the night. As he watched them flee, Cato lowered his sword and found that he was shaking. Whether from fear or exhaustion he no longer knew. Strangely, his sword hand was so tightly clenched round the handle that it was almost unbearably painful. Yet it took all the force of will he could summon to make his hand slacken its grip. Then awareness of his surroundings became more rational and he saw the line of bodies stretched out along the barricade, many still writhing and crying out from their injuries.

‘First and Sixth Centuries!’ Hortensius was shouting. ‘Keep going! Advance a hundred paces and halt!’

The Roman line moved forward, and slowly the flank centuries and supply wagons slipped through the gaps and resumed their place in the square formation, shepherding their surviving prisoners along with them. Only the rear two centuries remained on the far side of the barricade, steadily giving way under the onslaught of the Durotriges’ best warriors. While his century was halted, Macro ordered Cato to make a quick tally of their strength.

‘Well?’

‘Fourteen lost, best as I can say, sir.’

‘All right.’ Macro nodded with satisfaction. He had feared the butcher’s bill would be higher than that. ‘Go and report that to Centurion Hortensius.’

‘Yes, sir.’

Hortensius was not difficult to locate; a stream of orders and shouts of encouragement were ringing out across the sound of battle, even though the voice now carried the rasp of extreme exhaustion. Hortensius received the strength report and did a quick mental calculation.

‘That makes our losses over fifty, and there’s the rear cohorts to go yet. How long until dawn, do you think?’

Cato forced himself to concentrate. ‘I’d guess four, maybe five hours.’

‘Too long. We’ll need every man on the formation. Can’t spare any more for guard duties…’ The senior centurion realised he had no alternative. ‘We’re going to have to lose the prisoners,’ he said with unmistakable bitterness.

‘Sir?’