Both sides shouted, no longer in any ordered way, and the sound mixed with gasps of effort and pain. There were bodies on the ground behind the Roman line, most of them Britons and many still moving. One of the optiones stationed at the rear of the formation began jabbing down with the spike on the butt of his staff of office, until another of them yelled at the man to do his job and make sure that the men stayed in formation.

Ferox could not see the fighting clearly, just the backs of the Roman soldiers, but he could tell that they were going forward, step by step. There was a ripple as a Briton hacked down a man in the front rank and jumped into his place, so that the soldiers behind rained blows on him until he dropped. The gap was closed up as one of the men stepped forward, and the line pressed on.

Masclus led his second turma forward as skirmishers because the first had used all their javelins. Ahead of them the Britons were bunched together, crouching in the hope of gaining more shelter from their little shields. Some threw javelins, little axes or even stones at the fast-moving horsemen, but the missiles went wide or bounced off shields and none of the auxiliaries fell.

‘A little more of this, and we charge, lads,’ Ferox told his men.

‘Better put your other hat on then,’ Vindex said, and the centurion realised that he still wore his old felt hat. He reached back and unfastened his helmet.

‘You go back to your men,’ he told the scout.

There was a cheer from II Augusta as the Britons at last gave way, going back fifty paces before they stopped. Some were wounded or too slow and were cut down by the legionaries, many of whom streamed after the retreating enemy.

All along the front the same thing was happening. The Britons had held the Roman onslaught longer than Ferox had expected, but now they went back and both sides drew breath.

‘Halt! Halt. Form up!’ the senior centurion of II Augusta shouted at his men. Ferox could see the high transverse crest of the officer’s helmet as he rushed up and down in front of them. The other centurions took up the cry, and after a little confusion the legionaries obeyed. Optiones in the rear helped re-form the line, and wounded men were sent back out of harm’s way, apart from a few who refused to leave the front rank.

A single big flake of snow tumbled down and landed on the mane of Ferox’s horse. It did not melt and sat there, looking very white against the rough black hair. Other flakes followed and there was a glow in the clouds that promised plenty more.