‘Ready! . . .’ Vespasian raised his arm in case the order could not be heard above the din of the enemy.

‘Ready!’ The centurions relayed the order to their men, and turned back to watch for the legate’s next order. Below them, the Britons, howling their war cries and straining every muscle to make sure they smashed into the Roman shields at full pelt, surged forward in a writhing mass of helmets, spiked hair, tattooed bodies and flashing and glinting blades.

‘Release!’ roared Vespasian, sweeping his arm down. At once the centurions repeated the order and the men hurled their right arms forward; their effort filling the air with a chorus of strained grunts. The dark shafts of the javelins rose up and out like a thin curtain of water thrown up from a rock cast into a pond. Already the centurions were bellowing out orders for the second rank to pass their weapons forward to replenish the front rank. The iron tips of the first volley passed the apex of their trajectory and dipped down towards the Britons. The foremost ranks of the enemy charge faltered as they beheld the peril. Some sprinted forward, hoping to run in under the volley, others covered themselves with their shields and prepared for the impact. The rest - light spearmen and swordsmen with no armour - either went to ground, or gazed upwards, hoping to duck, or dodge any javelin that fell towards them.

The volley crashed down in a rolling clatter and thudding that turned to grunts and screams as the javelins found their targets. Then, as if an invisible hand of some giant god had swept through the front ranks of the Britons, scores of them were bowled over and fell to the ground. Other men tumbled over their fallen comrades and sprawled amid the tangle of limbs, shields and the long shafts of the javelins. Then the men behind them forced a way through and charged on up the hill.

‘Javelins! . . . Ready! . . . Release!’

Again, a wave of the Britons was taken down, adding to the confusion of those already lying stricken on the slope. Then the third and the fourth volleys swept into the enemy massing about the crest of the hill and added to the ruin of the Britons’ first attack. No longer were they screaming out their war cries. Instead, a deep murmur of shock rippled back down the slope, and at that moment the legate decided to press home his temporary advantage. ‘Swords out!’

‘Swords out!’ the centurions shouted, and a sharp metallic rasping echoed round the hilltop.