The century continued to fight its way forward, but it was evident to those on the gatehouse that the pace was slackening. Even so, they reached the oxen of the first wagon and forced enough of a gap through the swirling ranks of the enemy to permit the wagon to drive through, rumbling free of the mêlée towards the open gates. The second and third wagons followed, and the surviving auxiliaries struggled to form up with their legionary companions. Vespasian dismounted and threw himself into the fight alongside his men. For a moment Cato felt a pang of anxiety as he lost sight of his legate; then the distinctive red crest atop Vespasian’s helmet appeared amid the wild, shimmering mass of gleaming helmets and bloodied weapons.

Cato leaned over the palisade to watch the wagons pass beneath the gatehouse, each one laden with stacks of amphorae packed in straw. A small quantity of grain and oil would be saved, then. But that was all. As he looked up he saw that the last two wagons had fallen into British hands, their drivers and handlers lying slaughtered beside them. Only one last wagon was contested, and as Cato watched, the Britons began to drive the Romans back from it.

‘Look there!’ said Macro, pointing away from the mêlée. The British chieftain had gathered most of his chariots about him and was leading them wide round the fighting, clearly aiming to crash into the rear of the Roman line. ‘If that lot catches them before they can reach the gate, the lads will break.’

‘Break?’ Cato snorted. ‘They’ll be cut to pieces . . . If only they see the danger in time.’

The Roman line was giving ground steadily under the weight of the Britons’ attack. The men in the front rank thrust and blocked, wholly concerned with killing the enemy immediately to their front, while their comrades behind them were glancing nervously over their shoulders and edging back towards the safety of the gate. With a wild shout of triumph the charioteers suddenly whipped their ponies on, charging towards the narrow gap between the legionaries and the gatehouse. Even where he stood Cato could feel the walkway tremble beneath his feet as the ponies’ hoofs and the chariot wheels shook the ground.