We halted a little distance away to view the battle array, and to catch our breath before attacking. The kings gathered round us to hold council. 'They think to take us here,' observed Arthur.

'And they may just do it,' remarked Idris. 'Look at the length of that line. We cannot equal it – we will be stretched too thin. They can easily surround us.'

I, for one, had had enough of his crabbed lack of faith. 'If this be courage, Idris,' I told him, 'you show it in a most peculiar way.'

Gwalcmai laughed, and Idris subsided, his mouth pressed into a bloodless line.

'We will strike them in the centre, there,' said Arthur, who had been studying the enemy; he pointed to the thickened mass before us. 'The Angli fight like Saecsens, but they are even more afraid of the horses. Therefore, the ala will force them back across the ford and cut the line in two. When this happens the two ends will be drawn in together to fill the void.'

'They will circle and surround us, Duke Arthur.' It was Maglos this time.

'Yes,' replied Arthur coolly, 'and when that happens our footmen will come at them from behind.'

'But we will be trapped,' Bedegran insisted.

'There must be some bait in a trap,' Gwalcmai told him, thus saving me the trouble, 'or the rat will not put his nose in.'

'I do not like it,' sniffed Idris. 'It is needlessly risky.'

I turned on him. They fear the horses! Have you not seen how they flee the sight of them? By the time they close on us, our own warriors will be at their backs and they will be the ones surrounded!'

I turned to find Arthur staring at me. 'What? You think yourself the only one who knows the head of a spear from its butt?' I demanded.

Arthur turned to the others. 'Well? You have heard Bedwyr. He will lead the charge to the centre. Bedegran and I will lead the footmen as before. May God go with us.' And he rode off to join the foot soldiers waiting beside the river.

Idris was right: Arthur's plan was risky. But it made the best possible use of our few horses. By using them to keep the enemy off balance, so to speak, our fewer numbers were not such a disadvantage.

The Angli thought to attack while we were still undecided. And with a tremendous roar they came at us on the run. 'Spears ready!' I called, sheathing the sword and retrieving my spear. I threw the reins forward and my horse lumbered into a trot. The a/a formed up in wings on either side of me.

Gathering pace, the trot became a run and the run a gallop. Gwalcmai's voice rose above the thunder of the hooves, and an instant later we were all waning in that high, eerie war chant of his. I felt the hot blood rising in my veins and the icy calm of the battle frenzy descend over me.

And it was no longer Bedwyr riding headlong towards the onrushing enemy. I was a flame, a burning brand flung into the wind. My heart soared within me with the song of battle.

My movements were immaculate, my thoughts bright and sharp as crystal.

The eyes in my head looked out and noted the battle array before me. We were closing… nearer… nearer…

I was through the line and pulling up hard. A dozen Angli sprawled on the ground around me: some of them dead where they had dropped, others struggling to rise.

I saw one foeman staring stupidly at his shield which seemed to have become stuck to his chest. He pulled at it and the shield fell away, revealing a slender length of a broken spear, jutting out from between his ribs. My own spear had mysteriously lost half its length. I threw it down.

Drawing my sword, I wheeled my horse to survey the carnage. The force of our charge had indeed collapsed the centre of the line: the damage fifty horse can do is considerable. What is more, we had not lost a single rider.

But our assault had carried us further into the centre than I could have believed possible; we were at the ford, almost in the water. The Angli were not slow to react. Instantly, they closed on us and we were surrounded. Yet, even as they filled the rents we had made in their battle line, I heard Arthur's hunting horn sounding high and clear.

I gathered the ala to me and we formed up to fight towards Arthur. The battle had become close. We were pressed on all sides, but the Cymry kept their heads and we moved forward, slowly, and with difficulty, for the Angli, in their desperation, gave ground grudgingly.

Then, when all was committed to Arthur's plan, the worst thing possible happened: the Picti, so far absent from the fight, suddenly appeared, streaming down from the hillside, coming in behind Arthur. As soon as they were within striking distance they loosed then* hateful little arrows.

So there we were, outnumbered and twice surrounded. Of all possible positions for an army, there are not many worse.

Arthur did what he could, sending Idris' troop to deal with the Picti. Naturally, this weakened his own force. Seeing Idris break away, the Angli and Irish responded with almost hysterical fury.

Giving forth a tremendous howl, the barbarian rose up like a great sea wave and Arthur was inundated. I saw him at the head of his troops on his white horse rising above them, and then he was gone.

'Arthur!' I cried, but my voice was lost in the battle roar. The seething waters of the enemy host closed over the place where he had been.

The ala drove into the thick of it. On the strength of steel alone we pushed a way clear – over the thrashing bodies of the foeman. May God forgive me, my mount's hooves scarce touched the ground!

We reached the ford. The water ran red; the river foam blushed crimson. Corpses floated, their limbs drifting. Caught on the rocks, the dead gazed with profound blindness into the darkening sky.

Once in the water, the going was easier – but only just. The Angli flung themselves at us with the ferocity of wild beasts. Swinging their axes, stabbing with their long knives, bawling, lunging, grappling.

We hewed at them like standing trees and they fell. But always there were more and more.

I strained into the welter, searching for Arthur. All was a chaos of flailing limbs and flashing weapons. I did not see him.

Now we were within range of the Picti arrows – though Idris had succeeded in moving them back somewhat, the wicked missiles still struck with deadly accuracy. The warrior to my left was struck in the shoulder, and one arrow glanced off my shield boss.

Grimly, we laboured on. The leaden sky deepened to the colour of fire-blackened iron. The wind gusted, driving the mist along the river. Rain began pelting down. The ground beneath our feet grew slippery. Blood and water mingled, flowed away. The battle proceeded.

Ever and again I cried out, 'Arthur! Arthur!'

In response I heard only the thunder of the fight, loud and sharp, pierced by hot oaths and agonized cries. And under it, the dull, droning rumble of running feet and horses' hooves…

Horses' hooves. That could not be what I heard, and yet I know the sound as well as my own heartbeat.

I raised my eyes. Out of the mist I saw a herd of horses racing into the valley, their shapes made ghostly by the rain. Swift as diving eagles, they thundered headlong into the midst of the fight.

Could it be? I looked again and saw the reason for this marvel. At the head of the stampede I saw two figures – one obscured by the mist and rain, but the other I knew: no one sits a saddle like Cai.

The enemy saw the horses at the same instant I did. A heartbeat later they were fleeing across the river. By the hundreds and thousands they fled, trampling over one another as they struggled across the ford.

We hacked at them as they fled, but they were no longer resisting. Stupid with fear, they abandoned themselves to our swords without thought.