‘There’s a few boats over that way.’ Cato pointed to the southern side of the camp. ‘I saw them when we approached the entrance to this place. We’ll take those.’

‘Then what, sir?’

Cato looked at him directly. ‘We have to warn the cohort, and get a message to Vespasian.’

For a moment Cato feared that Metellus would protest, but the legionary gave a faint nod of acceptance.

‘Right then, let’s move. When the gate opens, you move - fast.’

Cato turned, and worked his way over the puddles and heaps of filth towards the inside of the gate. It was fastened by a stout wooden bolt on the outside, a short distance from the top. While the others crouched down, silent and tense and ready to spring, Cato slowly rose up to the full extent of his height, peering over the gate at the dark backs of the two guards. He reached a hand over the top of the wooden frame and groped down for the peg that fastened the gate. While his eyes remained fixed on the guards Cato’s fingers crept down the rough surface of the wood until his arm was fully extended. Then he took a breath and rose up on the tips of his toes. This time the very tips of his fingers brushed the top of the peg. Cato strained to reach further but could gain no purchase on the wood shaft, and finally he withdrew and slumped back behind the gate with a sharp intake of breath.

‘Shite,’ he mouthed. ‘Can’t reach it.’

‘Try again,’ Figulus urged him. ‘On my back.’

The optio dropped on to his hands and knees and leaned gently against the inside of the gate. Cato placed a boot on the optio’s shoulder and gently raised himself up again, ignoring the grunt of pain from Figulus as the iron studs of Cato’s boot bit into his flesh. This time Cato could see clearly over the top of the gate and he carefully reached down to the peg and gently took up the strain. It had been firmly jammed into the receiver and he gritted his teeth and strained to pull it free. Then, at last, it shifted a little, then a little more. But this time it turned slightly with a faint squeak. Cato’s hand froze and his eyes flickered up towards the guards, just in time to see a head turn towards him.

There was an instant of terrible stillness as the boy looked at the gate in puzzlement. Then he snatched up his spear, scrabbled round and shouted at this comrade, ‘They’re escaping! Up! Stop ‘em!’