And so on. This was how the system was supposed to work. Thanks to its fast communications, detailed record keeping and flexible deployment the army, never numerically strong, was able to deploy rapidly and efficiently, focusing its energies exactly where they were needed most. The army itself was a high technology, Brigonius saw, honed and perfected over centuries of conquest.

Meanwhile the soldiers were individually preparing. Brigonius had worked with Roman soldiers for years. While they could sneer at the Brittunculi they had been posted to govern, they had come to seem disarmingly ordinary to him: ordinary fellows doing a job of work, wanting nothing but food, sleep and an occasional shag. But now he saw these men for what they were. In armour that fit like a second skin, wielding weapons with the casual intimacy of a lover's touch, they were barely human at all, he thought; they were slabs of muscles intent only on killing. And as they formed up in their tight disciplined units they seemed more formidable yet. Brigonius's heart felt heavy as he thought of the force that would face them, a rabble of disaffected Brigantian farm-boys stirred up by hotheads like Matto, armed with rusty weapons their grandfathers had been hiding in grain pits since the days of Cartimandua.

A month after the insurrection had been put down, governor Nepos travelled from Londinium to assess the damage for himself.

Nepos toured the forts and rode the length of the Wall, and spoke to his senior commanders, including Tullio. He returned to Eburacum for a few days to preside over the trials of the suspected ringleaders of the rising. And he announced, in the even-handed way of wiser Romans, that he would consider compensation for farmers who had lost significant chunks of land-always providing they could prove they hadn't taken part in the uprising themselves.

Then he came to Banna, where he ordered a review. Tullio, Annius and their staff were called in, as were senior officers from the forts, a couple of tribunes from each of the three legions, and the architect, Xander, with his sponsor Severa, and Brigonius and other local suppliers.

The meeting was fractious from the start. Nepos demanded of Tullio, 'How could this happen, prefect?'

'We had some failures of intelligence,' Tullio admitted, 'which have been put right. A failure of security too which has been tightened.' Brigonius could testify to that; he had the bruises inflicted by gatekeeping soldiers to prove it. 'But,' Tullio went on, 'we just didn't anticipate the way the attack unfolded. The Wall is designed to deal with attacks from the north, not the south!'

Nepos shook his head. 'I still find it hard to believe. This has implications for everything we are doing here. If this were to happen again-'

'It won't,' Severa said quickly. 'Governor, this was a bit of restlessness by unhappy Brigantian farmers. Once your more lenient policies are accepted-'

Nepos glared at her until she was silent. 'Madam, to my mind we are building for centuries. Perhaps Brigantia will be quiet for a season or two. But in time a new generation of young bulls will rise up who will imagine their grandfathers didn't go far enough-I've seen it all before. We must plan for all contingencies.'

A young man in brightly polished dress uniform stood and took the floor. 'And that isn't all we have to think about.' He bowed to the governor. 'Sir, my name is Galba Iulius Sabinus. I am a tribune of the sixth; my legate at Eburacum sent you his report on the new military dispositions.'

Tullio growled, 'The damn legions didn't deploy.'

'But they might have had to,' Sabinus said with effortless command.

Nepos nodded to the tribune. 'I've seen the report. You may summarise its findings, Iulius Sabinus.'

Sabinus was good-looking, strong-featured, with thick dark hair. Brigonius imagined he might actually be a native Roman-and if he was a tribune he must be of the senatorial class, in the course of a career which might one day lead him to a post like Nepos's own. Brigonius always reminded himself that to men such as Nepos and Sabinus, whatever happened in Britain was but an incident in a long career progression.

'We of the sixth, concerned about the practicality of the Wall even before the uprising, have since mounted a major exercise to test its utility. All this is detailed in the report…'

The idea of the Wall was that in the event of major disturbances to the north, the legions would deploy from their forts in the rear, march through the gates, and meet the enemy in open battle north of the Wall. When detachments of the sixth had actually tried this they hit problems. First you had to walk a few miles to the Wall itself. Then you had to break formation to make your way to one or other of the gates and file through, and just as Tullio himself had anticipated, legionaries in full battle armour found themselves queuing behind farmers' wagons and herds of sheep. Even on the other side of the Wall you then had to form up again into marching order. During all this time you were terribly vulnerable to attack.

'It just didn't work,' Sabinus said with bold bluntness.

Tullio said, 'In fact it's worse. In some places you have to cross the river to get from the forts to the Wall! The Wall's been my baby, and I hate to say it, but we should pull down the whole wretched thing. We did better under Trajan without a Wall at all.'

Xander stood immediately, plump, anxious, shaking off Severa's restraining hand. 'We must finish what we have started,' he insisted in his heavily accented Latin. 'You can't judge the performance of the Wall as a system when it is not completed, any more than you can expect a cart to run on only two wheels. When my design is fully realised-'

'It's still not going to work,' Tullio said bluntly. 'Because it will still have the flaws we have identified today. A vulnerability from the south. Inadequate crossing points.'

Sabinus nodded. 'My legate would agree. We have to think too of the longer term implications for the empire as a whole of such a static, frozen frontier. The economic consequences alone-'

Nepos held up a hand to silence him. 'Now your education is showing, Iulius Sabinus,' he said dryly. 'I have only a few years in this chair, and I have to think of the short term, not the long.'

Severa said quickly, 'In the countryside the Wall has already become a highly visible sign of Roman strength. To abandon it now would be a clear sign of weakness. A retreat.' Brigonius saw she was trying to manipulate the soldiers' sensibilities, trying to keep some control of the project.

Nepos sighed. 'Unfortunately I have to agree with you about that, madam. The Emperor would not accept an abandonment. It would harm him back in Rome. The Wall exists, for better or worse. We have to consider where we go from here, not where we would wish to have started from.' He turned again to Xander. 'We will not obliterate your precious monument, architect. But how would you modify it to correct its deficiencies?'

Xander, unfortunately, had retreated into a shell of hurt pride. He all but shouted at the governor, 'The design cannot be modified! It must be expressed!'

Tullio raised an eyebrow, and a ripple of exasperation passed among the Romans in the room, Brigonius thought. Greeks will be Greeks.

Sabinus, ambitious, saw his chance. 'If I may, governor? I've taken the liberty of drawing up a few modifications to Xander's design that might accommodate the objections we've heard today.' He held up a scroll. On Nepos's nod of permission, he spread this on a low table before the governor. Brigonius saw it was a rough sketch done in charcoal of the Wall curtain, forts and ditches.

'To begin with,' Sabinus said, 'the vulnerability at the rear. You can see that I've added a further earthwork on the south side.' The cross-section he had sketched showed a ditch some twenty feet wide at the top and ten deep. There were mounds twenty feet across to either side, each set some thirty feet from the lip of the ditch. 'This earthwork will be set back from the Wall to create a protected zone to the Wall's south, an "annexe" if you will, where civilians will be excluded or controlled. There will of course be controlled crossing points and causeways at the forts.'