The crew captains pushed the release levers forward and Vespasian’s ears resounded to the sharp crack as the torsion arms sprang back. A thin veil of dark lines streaked up towards the palisade. As was always the case, a number fell short and buried themselves in the slopes. Others overshot and disappeared way beyond the palisade — where they could still be a hazard. The crews would mark the fall of their shots and adjust the elevation accordingly. The vast majority, however, struck home in the first volley. Vespasian had seen the impact of such firepower a few times before, but even he marvelled at the destruction it caused. Whole timbers in the palisade were shattered by the heavy iron-headed bolts, splintered fragments whirling into the air, and the palisade soon had the appearance of a mouth filled with bad teeth.

The second volley was more ragged than the first as the more efficient crews fired earlier, and soon the disparity in loading times led to an almost continuous crashing from the released torsion arms. The palisade was brutally beaten down, and most Durotrigan warriors foolhardy enough to mount the rampart behind and shout their defiance paid the price. Vespasian idly watched as one big man waved a spear, until a bolt caught him high in the chest and simply whipped him bodily out of sight. Another was struck in the face, the blow completely shearing off the man’s head. His torso remained upright for a moment, then collapsed.

Less than an hour later the defences about the main gate were in utter ruin, the stakes that had made up the palisade reduced to stumps, streaked with crimson. Vespasian motioned to his senior tribune. ‘Send the cohort in, Plinius.’

The tribune turned to the trumpeter and ordered him to sound the advance. The man put his lips to the mouthpiece and blew a sharp series of rising notes. As the first call echoed back from the ramparts, the centurions of the First Cohort gave the order to advance, and in two broad columns they began marching towards the approach ramps. The sun was low in the sky, and the backs of the men’s helmets threw back a thousand reflections into the eyes of their comrades watching the fight from the legion’s fortified camp. A substantial reserve of men stood ready to reinforce the First Cohort should it be roughly handled by the Durotriges. More men had been sent out during the night to position themselves round the fort and stand off, ready to intercept any enemy attempting to flee the far side of the fortress should the gate fall. Nothing had been left to chance.