The centurion commanding the garrison glanced towards the chariots and bellowed a warning. At once the legionaries and auxiliaries broke away from their enemy and ran for the gateway, Vespasian amongst them. On the gatehouse Verica cupped his hands and shouted an order to the men lining the palisade. Throwing spears were snatched up and arrows notched to prepare a covering barrage for the fleeing Romans. Already they were streaming in through the gates, but some were not going to make it. The oldest soldiers, struggling pitifully with their heavy equipment, were falling behind. Most had cast their shields and swords aside and threw themselves on, glancing to their right as the chariots closed in, the manes of the ponies whipping out as their nostrils flared and their mouths foamed; above them the savage expressions of the drivers and the spearmen, exulting in the imminent destruction of the Romans.

Centurion Veranius, true to his kind, still carried his shield and sword, and trotted along with the last of his men, shouting at them to keep moving. When the chariots were no more than twenty paces from him he realised he was a dead man. Veranius stopped, turned towards the chariots and raised his shield, holding his sword level at his waist. As Cato watched, feeling sick in his guts, the centurion glanced up at the gatehouse and smiled grimly. He nodded a salute at the line of faces witnessing his final stand, and turned his face towards the enemy.

There was a scream, abruptly cut off as the chariots rode down the first of the stragglers, and Cato watched as the chain-mailed bodies of the legionaries were crushed to a pulp by hoofs and wheels. Veranius charged forward, stabbing his sword into the chest of a lead pony, then he was knocked down and disappeared under the confusion of harnessed horse-flesh and the wicker superstructures of the chariots.

With a grinding thud the gates were heaved back together and the locking bar crashed back into its receiving sockets. The chariots slewed to a halt in front of the gate and then the air was filled with shouts and shrill agonised whinnies as the javelins and arrows of Verica’s men on the palisade rained on to the dense mass below. The Britons answered with their own missiles and a slingshot cracked against the palisade just below Cato. He grabbed Macro by the shoulder and drew him back towards the ladder leading down to the inside of the ramparts.

‘There’s nothing we can do here. We’re just in the way.’

Macro nodded, and followed him down the ladder.