The men stilled as the order was passed back and then Cato strained his ears to discover the source of the vibrations, growing ever stronger. Around him the rain pattered down steadily and the low wind made a faint roar in his ears as it ruffled the tips of the long blades of grass. Then a dark shape appeared around the edge of the copse they were making for. Another joined it, quickly followed by a steady stream of other shapes. The sound of a horse whinnying carried across the plain towards the men hiding in the grass. Cato eased himself down as he strained his eyes to pick out any detail. The horsemen suddenly altered course, seemingly heading directly towards Cato.

‘Shit!’ he hissed, hand instantly going to the handle of the sword he had stuck in his belt. Then he realised they couldn’t have been spotted by the horsemen. It was far too dark for that. Nevertheless . . . ‘Stay down! Pass it on. Stay down, but have your swords ready to hand. No one makes a move before I do.’

The legionaries flattened, hugging the earth, as the order was hurriedly whispered back down the thin column. Cato turned back towards the horsemen, no more than two hundred paces away. At least two squadrons of scouts, he calculated. More than enough to wipe them out. And still they came on, heading for the camp, wholly unaware of the presence of the escaped prisoners - for the next few moments at least, Cato thought bitterly, as he pressed himself down, his cheek juddering from the growing vibration as horses’ hoofs pounded closer.

At the rear of the column Figulus thrust his hand forwards and grabbed a fold of Proculus’ tunic.

‘For fuck’s sake! Stay down!’

‘No! No. We must run. Run for it!’

Proculus started to rise up from the grass, kicking out at the arm that grasped his tunic. ‘Let go!’

Figulus glanced at the approaching horsemen, and instinctively rose up behind Proculus. He threw himself forward, smothering the man as the two of them crashed back to the ground. The optio slammed the pommel of his sword into the side of the legionary’s head and Proculus went limp at once. Figulus took no chances and lay across the inert body, sword poised at the man’s throat as the horsemen rumbled towards them.