As Septimus’ men began to pass through the gap left open for them, Cato called out to the optio, ‘Form your men up behind me. We can’t afford to divide the century any more.’

Septimus nodded and turned to deploy his men as the five fresh sections under Cato’s command took over the fight.

Tightening the grip on his sword and hefting the shield forwards and up, Cato stepped forward and pushed into the front line. At once a heavy blow from an axe drove his shield back into him. But this dense fighting at close quarters was what the Roman legions trained for, and Cato rode back with the blow. Then, transferring his weight on to his back foot he launched himself against the enemy and felt his shield smash into a body with a loud thud. There was a grunt of pain and surprise, and Cato rammed his short sword forward, round the edge of the shield, and was rewarded by the shock of an impact that ran up his arm. He withdrew the blade, noting the blood dripping six inches from the point. A fatal injury in all probability and, he realised with surprise, he had never even seen the man who had suffered it.

Another impact on his shield, and this time fingers curled over the top of it, inches from his face, and wrenched it back. Cato held on with all his strength, then swung his helmet forward, crushing the enemy’s knuckles with the solid iron cross brace above his brow. The fingers were snatched back and Cato thrust his shield forward, into space this time, and then stepped back to draw a breath.

‘Sixth Century! Sixth Century, give ground! Optio?’

‘Sir!’

‘Call the time!’

‘Yes, sir . . . One! . . . Two! . . . One! . . . Two!’

At every command the men in each rank carefully retreated a pace in the face of the enemy. Cato was content to yield control of the pace to the optio. Once the fighting started in earnest the world of the men engaged in a deadly contest became a whirling chaos of weapons clashing, men grunting, cursing and screaming their defiance and agony. Instinct, honed by relentless years of training, took over, and any sense of the passage of time was lost in the savage intensity of surviving the moment.

There were few chances for lucid thought as Cato fought to stay alive, but he snatched glimpses of Caratacus, only fifteen or twenty feet away, urging his warriors on, bellowing a war cry that carried clearly over the cacophony of battle and drove his men to new heights of ferocity.

‘One!’ Septimus called out.

If only Caratacus could be killed, Cato managed to think, as he drew back another step. He chopped at a bare foot raised to kick at his shield.

‘Two!’