The sacrifice of the scouts only delayed their enemy for a short while, by which time the wagons and their escorting infantry were only two hundred paces from the gateway. Those on the wall shouted encouragement and wildly beckoned to them.

On came the Durotrigans, a seething mass of men and chariots, closing with their prey. The auxiliaries prepared to receive the charge. The dark slivers of the remaining javelins curved through the air and lanced down into the enemy. Cato saw one strike the head of a chariot horse and the animal reared up and spun to one side, dragging the chariot over and crushing its driver and spearman. The Britons swept past, unheeding, and threw themselves on the shields and swords of the auxiliaries, pushing them back on the retreating wagons.

Cato heard the steady tramp of marching boots from behind and turned to see the head of the garrison emerge from the heart of Calleva and march up to the gate. Below the wooden flooring of the gatehouse tower Cato heard the graunch of the heavy timbers of the gates as they were heaved open ahead of the legionaries.

‘About bloody time!’ Macro grumbled.

‘You think they’ll make a difference?’

Macro watched the desperate fighting engulfing the rear of the supply column and shrugged. The sight of the legionaries might just make the Britons pause in their onslaught. Over the last two years the natives had come to fear the men behind the crimson shields, and with good reason. However, these were the oldest of the veterans, lame men no longer able to keep up with their comrades, and those malingerers who could no longer be trusted to stand their ground in pitched battle. The instant the enemy realised the true calibre of the men they were facing all would be lost.

The first ranks of the garrison emerged from beneath the gatehouse. The centurion barked an order and the column changed formation, men spilling out on either side of the track to create a line four deep. As soon as the manoeuvre was complete the line moved forward towards the embattled supply column. The rearmost ranks of the Britons turned to face the new danger and slingers and archers loosed their missiles against the Romans. The barrage rattled harmlessly off the shields and then the noise ceased as the enemy infantry stepped forward to meet the legionaries. There was no wild charge from either side: the two lines simply came together in a rising clatter of ringing blades and dull thuds of shields. The legionaries pushed towards the first wagon, remorselessly carving a path through the Durotrigans.