Then one man, taller than the others, came from the house and pushed through his companions. He stood at the edge of the stone wharf and stared at us.

And I cursed. It was Waormund. I stared at him and he stared at me, and he recognised me. I heard his bellow of rage, or perhaps of challenge, and then he was shouting at the men around him and I saw them running towards the lethal-looking ship. I swore again.

‘What?’ Father Oda asked.

‘Speed the rowers,’ I told Finan.

‘Speed them?’

‘We’re being pursued,’ I said. I looked up at the sky and saw that darkness was still many hours away.

And we were no longer safe.

The ebbing tide was nearing low water, which meant it was running faster and gave us some help as, with the river’s current, it swept us downriver. Finan was hammering the time with a stave and he quickened it, but the oarsmen were too tired after rowing upriver against the ebb. The current, of course, would help our enemy as much as it helped us, but I hoped it would take Waormund a long time to assemble sufficient oarsmen, but hope is never something to rely on in warfare. My father had always said that if you hope the enemy will march east, then plan for them marching west.

We passed the old Roman fort that marked the eastern extremity of the old city and I looked back and saw my father had been right. The ship was already pulling away from the wharf, her rowers turning the longsleek hull to follow us. ‘It’s not a full crew,’ Finan said.

‘How many?’

‘Maybe twenty-four oars?’

‘They’ll still catch us,’ I said grimly.

‘That’s a big ship for just twenty-four oars.’

‘They’ll catch us.’

Finan touched the cross at his neck. ‘I thought someone said this was a fast ship?’

‘For her size, she is.’

‘But the longer a ship, the faster she is,’ Finan said unhappily. He had heard me say that too many times, but had never understood why that was true. I did not understand it either, yet I knew the pursuing ship must inevitably catch us. I was steering Brimwisa to follow the huge horseshoe bend in the river that would sweep us southwards before curving north. I was using the outside of the bend, which was a longer row, but there the current was fastest and I needed all the speed I could find. ‘There are men at her prow,’ Finan said, still staring behind.

‘They’re the ones who’ll board us,’ I said.

‘So what do we do? Go ashore?’

‘Not yet.’

The current was racing us southwards. The river was low, with wide stretches of glistening mud on each bank, and beyond them little but desolate marshland where a few hovels showed where folk made a living from trapping eels. I turned and saw our pursuer was gaining on us. I could see the mailed men in the prow, see their shields with Æthelhelm’s leaping stag, and see the afternoon sun glinting from spearheads. Those men planned to jump down onto the Brimwisa’s deck. ‘How many in the prow?’ I asked Finan.