Vespasian could well imagine the anger with which General Plautius would greet news of such a setback. Aulus Plautius had been appointed by Emperor Claudius to command the Roman army whose task was to add Britain and its tribes to the Empire. Despite Plautius’ victories over the barbarous tribes the previous summer, Caratacus had raised a new army and still defied Rome. He had learned much from last year’s campaigning and refused to take the field against the Roman legions. Instead, he detached columns of men to attack the supply lines of the ponderous Roman war machine. With every mile General Plautius and his legions advanced, those vital supply lines became more vulnerable.

So the outcome of this year’s campaign depended on whose strategy triumphed. If General Plautius succeeded in forcing the Britons to face him on the field of battle then the legions would win. If the Britons could avoid battle and starve the legions, they might weaken them enough to force the general into a perilous retreat all the way back to the coast.

As Vespasian and his escort galloped up to the crest of the ridge the blasts on the war horns became more strident. Now the soldiers could hear men shouting, the sharp clang of weapon striking weapon, and the dull thud of blows landing on shields. The long grass was silhouetted against the clear sky, and then Vespasian beheld the scene on the far side of the ridge. To the left lay Calleva, a huge sprawl of thatched roofs of mainly squalid little dwellings, ringed by an earth rampart and palisade. A thin haze of wood-smoke hung over the town. A dark gash of churned soil marked the track leading from the tall wooden tower of the gatehouse towards the Tamesis. On the track, half a mile from Calleva, only a handful of wagons remained of a supply convoy, protected by a thin screen of auxiliary troops. Around them swirled the enemy: small clusters of heavily armed warriors and lighter troops armed with slings, bows and throwing spears. They kept up a steady rain of missiles on the supply convoy and its escort. Blood flowed from the flanks of injured oxen, and the path of the convoy was dotted with bodies.

Vespasian and his men reined in as the legate briefly considered what to do. Even as he watched, a group of Durotrigans rushed the rear of the convoy and threw themselves on the auxiliaries. The commander of the convoy, clearly visible in his scarlet cloak as he stood atop the driver’s bench of the first wagon, cupped his hands to bellow an order and the convoy slowly halted. The auxiliaries beat off the attackers easily enough, but their comrades at the front of the column provided a static target for the enemy and by the time the wagons were on the move again several more of the convoy’s escorts lay sprawled on the ground.