A warrior appeared on the crest, and in a moment there were dozens more alongside him. Rufus’ men cheered, and the Tungrians and little detachment of legionaries charged up towards them. That was always tiring, even for a short distance, but the men pounded up the hill. Ferox could not hear the order, and a shift in the wind wafted a mist of smoke over the charging Romans so that it was hard to see. There was no mistaking the ripple in the formation as the first rank threw spears or pila, then the second and then the third. Warriors fell all along the crest and then the legionaries and Tungrians ran into them, and even if they were panting, they charged with spirit.

‘Don’t wait too long,’ Ferox said softly, worrying that the young centurion would get carried away with his success. ‘Come back, back.’

He realised that he was holding his breath, so let it out and saw the ragged line of Romans turn about and march back down this side of the crest. The top of the pass was covered in bodies, and Rufus’ men had inflicted heavy losses on the boldest of their enemies. There were also two Tungrians and a legionary wounded so that they had to be carried, taking more men away from the fighting.

‘Ready, lads. Our turn next!’ Ferox told the auxiliaries. Once they were safely behind the crest, Rufus ordered his men to double down the slope. It was hard to keep at a steady pace going downhill, especially burdened with bulky shields and wearing armour and helmets, and by the time they passed Ferox and his men the legionaries and auxiliaries were half running, half stumbling along, formation ragged.

A lone warrior appeared on the crest. He was slim and tall, with mail armour, a red-and-white-striped cloak and a bronze helmet. Everything about the man seemed to glow, apart from his shield, which was drab and plain.

‘Step back five paces, slowly now.’ The Tungrians obeyed Ferox’s quiet order. ‘When the time comes, second rank to throw their spears. If I say charge we go ten paces and then stop. If I say hold we hold, and if I say run you follow me and run as if the demons of hell are behind you.’ He saw surprise on the auxiliaries’ faces, and was pleased that there were a few grins.

Britons appeared all along the crest, stepping up around the lone warrior. Tall carnyxes began to blare out their challenge.

‘Step back,’ Ferox ordered. ‘And another pace.’ He glanced behind and saw that Rufus had turned and re-formed his men, but they had gone much further than he had wanted and were a good hundred and fifty paces away. That was always the problem with a withdrawal. Men hurried back, going faster and running for longer than they were supposed to until the officers managed to stop them.