They worked their way along a track already churned up by forty thousand pairs of boots, tens of thousands of hooves. First they cleared the central track of undergrowth, and then dug out ditches to either side, heaping up the dirt along the spine of the road. They piled large, heavy rocks on top of the ridge of dirt, and then a layer of smaller rocks, and finally gravel was shovelled out and spread crudely. The smaller rocks and gravel were hauled along in carts, but the heavy rocks were scavenged locally - mostly from the dry stone walls of local farms, but there were no farmers around to complain. At last the soldier-engineers walked up and down along the newly laid stretch of the road, ramming down the gravel with heavy posts.

As the soldiers worked, under the pleasantly warm British sun, they sang. Many of their work-songs were in Latin, but Agrippina recognised some Gallic, and even a little Germanic. Rome’s soldiers did not only come from Rome these days.

Agrippina had seen Gaul; she knew what the future would hold. From this beginning the roads would spread out across the country like ivy over a wall, bifurcating and firing off their straight-line segments, until every corner of the land was reached. Messages would flash along the roads fast as thought, and the next time the soldiers needed to march this way they would be able to make much faster progress than today, through the mud and dirt. And in the future the young fighters of Britain, who today were preparing raids against the advancing Romans, would be marched away along these roads to go fight in Germany and Thrace and Asia, far from the misty cool of their homeland. Thus the empire absorbed its enemies and used them for its own further expansion—

A hand was clamped over her mouth. Agrippina struggled, but she was pinned to the ground. Her mind flooded with awful memories of that night on the beach. But then the weight shifted off her back, and she was able to twist and see the broad, dirt-streaked face of Braint, the farmer.

‘Sorry,’ Braint hissed. ‘Didn’t want you yelling out.’

Agrippina tried to control her anger. ‘You shouldn’t have done that.’

‘Well, you should be watching your back,’ Braint said. She crawled deeper into the undergrowth, and winced.

For the first time Agrippina noticed that Braint’s leg was bleeding. ‘What happened? Were you found?’

‘Nearly. I gashed my leg on a rock, and lost my knife, but I got away. Dodgy work, this spying. No wonder they gave it to us women.’

‘You need to tie up that cut. Do you want to borrow my knife?’