While Septimus took another step forward and asked again, more forcefully, Cato heaved himself up on to the wall and reached down to help Macro up. Then, making sure that the guard’s attention was fixed on Septimus, they lowered themselves down the other side of the wall, straining the muscles in their shoulders and arms, and let go. Their boots crunched audibly on the filth and rubbish that had gathered at the foot of the wall. The guard started and looked round quickly. His eyes widened and in an instant he snatched up his club and was on his feet, his meal tumbling to the ground in front of the stool.

‘I see! Thought you’d play a trick on me, eh? One comes from the front, while his pals take me from behind, eh?’

He lowered himself into a crouch, backed against the gate and swung his club to and fro. Cato could see that there were nails driven through the end of the club and could well imagine the damage those vicious points could do to a man’s flesh. He raised a hand.

‘Easy there. Our mistake. Come on, lads, this one’s too tough for us. Let’s be off.’

Septimus circled round the guard to join the others and then the three men backed away and turned to walk quickly along the wharf in the direction of the Boarium. The guard laughed nervously and blew a loud raspberry after them.

‘Yes, piss off then, you wankers! If I see your faces round here again then you’ll feel the kiss of my little Medusa here!’ He thrust the head of his club after them.

‘Bastard could do with a lesson in manners,’ Macro grumbled, slowing his pace until Cato grasped his shoulder and urged him on.

‘Not now. Let’s get out of here before he remembers me.’

Septimus turned to Cato. ‘Did you find anything?’

Cato briefly explained what they had seen and the imperial agent’s expression became anxious. ‘Damn. We need that grain.’

‘What about that convoy from Sicilia?’ asked Macro. ‘I thought that was going to save the situation for the Emperor.’

‘It will, when it arrives. But the extra grain would have been good insurance in case there was a delay in the arrival of the convoy. Now it all hinges on its arrival. Pray to the gods that it arrives safely. The spectacle that Claudius is putting on up at the Albine Lake will only divert the mob for a short time.’

They walked on in silence for a moment before Cato gave a dry chuckle.

Septimus looked at him sharply. ‘What?’