‘Thanks.’ Macro smiled, then launched himself across the gap between the beds and with his spare hand grabbed Scrofa by the neck and slammed his head against the rough stone wall of the cell. ‘Take his hand, Cato!’

Cato took an instant to recover from his friend’s sudden assault on the prisoner. Then he leaned across, grabbed Scrofa’s left hand in both of his and held it tightly as Scrofa tried to wrench it back. Macro punched the pommel of the dagger into Scrofa’s kidneys and the man gasped in agony.

‘No more struggling, understand?’ Macro snarled, and waited until the other nodded quickly. Then Macro turned back to Cato. ‘Hold his hand flat on the wall there, where he can see it. Good. Now then, Scrofa. This is your last chance. You’ll give me the answers I’m looking for, or I’ll cut your thumbs off. To start with . . .’

Macro held the man’s neck in a tight grip with one hand while he took a firm hold of the dagger handle with the other, and lowered the edge of the broad blade towards the joint between Scrofa’s thumb and the rest of his hand. Scrofa’s eyes widened in terror and there was a thin keening noise in his throat before he managed to speak.

‘I swear to you - on my life - I know nothing! Nothing! I swear it!’

Macro lifted the blade away from the thumb and stared at Scrofa for a moment, scrutinising his expression. Then he clicked his tongue. ‘Sorry, I’m not convinced. Let’s see if the loss of one thumb can provide a little incentive. Cato, hold him still.’

Macro lowered the blade so that the edge pressed into Scrofa’s flesh. The skin split and there was a small trickle of blood as Scrofa cried out. Macro tensed his arm, ready to begin sawing through the muscle and bone.

‘Wait,’ said Cato. ‘I think he’s telling the truth.’

‘He’s lying.’

‘I’m not!’ Scrofa whimpered.

‘Quiet, you!’ Macro shook him by the neck and turned back to Cato. ‘What makes you think this worm’s telling the truth?’

‘He’s been set up by Longinus. Think about it. Longinus is shrewd enough to cover his tracks when he can. So he sends Postumus down here to stir things up. Only the previous prefect proved to be something of an obstacle to Longinus’ plans. So Postumus removed him. Scrofa is appointed to fill the gap.’

‘Why him?’

‘Because Longinus knows that he’s vain and greedy. I’ll bet you that Longinus told Scrofa that he had been picked for the post because he showed promise. I’d guess that he also encouraged him to go in hard on the locals to prove his mettle. Is that right?’

Scrofa nodded.