'That I do not doubt, brother,' replied the Pendragon evenly.

Cai burst into laughter – a loud whoop of mirth. Bedwyr turned in his saddle to regard him. 'Fifty thousand Picti waiting for us – each with a thirst for our blood. You find this funny?'

'Na, na,' Cai replied, 'I was only thinking. Remember when Cerdic took Bors prisoner?'

Arthur smiled. 'Of course.'

'You crushed his hopes quick enough when you said: "Kill him if that is what you intend… " Cerdic never expected that.' Cai indicated the valley before them. 'Medraut would swallow his tongue if you told him that!'

He laughed again and Arthur laughed with him. I realized I had never heard the Pendragon laugh aloud before. 'That I would like to see!'

Bedwyr regarded them both with contempt. 'You cannot take this red-haired bull-roarer seriously, Artos. It is Gwenhwyvar's life we are talking about.'

'Never fear, brother,' Arthur replied lightly. 'I know my wife – she will appreciate the jest.' He cast his eyes to the surrounding hills. 'We will take the high ground – here and here – ' he said, indicating the twin hilltops above the valley. He had become the War Duke once more.

'Cador will lead the right flank, and Ban the left… ' The Pendragon turned and began walking back down the hill to where the war host waited hidden in the valley. Cai and Bedwyr joined him and I hurried after, as the three began making their battle plan.

Upon reaching the waiting army, the Pendragon's orders were conveyed to his battlechiefs, and the warriors began moving into position at once. Arthur donned his war shirt and high-crested helm; he strapped Caliburnus to his hip, and slung Prydwen, the white battle shield with the cross of Jesu, over his shoulder. He took up Rhon, his spear, stout veteran of many fierce and fiery combats.

Each of his great captains dressed themselves for battle as well: Bedwyr, Cai, Gwalcmai, Gwalchavad, Bors, Llenlleawg and Rhys. Champions all, helmed and armed for the fight. It made my heart soar to see them flaunt Medraut's challenge.

When the High King was ready he mounted to the saddle, and the others joined him. They rode together into the crooked glen – Camlan, valley of death.

I stood on the hilltop beside Cador and watched, my heart beating in my throat. I knew not what would happen – feared the worst, but prayed for the best.

At first, it appeared my prayers would be answered.

As the Pendragon and his men moved down into the glen, Medraut appeared from his hiding-place in the ruined fortress. With him came Keldrych and the hostages, together with at least thirty Picti warriors – naked and blue-stained with woad, their long hair stiffened with lime and pushed into white, spiked crests. They had also limed their shields and the heads of their spears.

Halfway to the stream coursing through the crooked valley, Medraut halted. He had seen that the Pendragon rode forth armed, in contempt of his command. Medraut whirled round, his arm went up and he pointed to the hostages.

But Keldrych stepped close, and after a quick consultation they advanced as before. No doubt, Keldrych had explained to the hot-headed Medraut that killing the captives removed any advantage they held over Arthur. However it was, the Pendragon's iron-hearted defiance had proven true again.

The two parties met a little apart, the stream between them. Arthur dismounted, but the others remained in the saddle. Arthur and Medraut advanced to meet one another alone. I would have given my right hand to hear what passed between them, but from my lofty vantage I saw its outcome right enough.

They talked for a time, whereupon Medraut returned to where the hostages waited, surrounded by the Pied warriors. Gwenhwyvar stepped out from among the others; the tyrant took her arm and pulled her with him back to where Arthur stood. Cai's hand went to his sword. Bedwyr put out a hand to steady him.

Upon reaching the stream where Arthur waited, Medraut seized the queen. He shouted something – I heard its echo, but could not make it out. He struck the queen cruelly on the face and she fell to her knees.

Arthur stood as one carved of stone. Not a muscle twitched.

Medraut stood over the queen and grabbed a handful of her dark hair. He jerked her head up, exposing her throat. Steel glinted in his hand. A knife!

Medraut shouted again. Arthur made an answer.

The knife flashed as it rose high in the air and struck swiftly down.

My heart stopped.

I opened my mouth to scream. Arthur's spear was in the air before the sound left my tongue.

Straight and true, like God's swift judgement, the spear streaked across the distance between them. I have never seen a spear thrown so swiftly, or with such force. It struck Medraut in the chest and pierced him through.

Arthur was on him in the same instant, driving the spear deeper. But Medraut, heedless of his wound, grasped the spear in his hands, and pulled himself up the shaft towards Arthur. He slashed wildly with the knife and caught Arthur a glancing blow.

Arthur dropped the spear and the traitor fell back writhing on the ground. The Pendragon drew Caliburnus and struck off Medraut's head.

I saw this clearly – and just as clearly saw Keldrych raise his spear and signal the attack. Instantly, the glen was alive with Picti! They came squirming out of the very ground it seemed – leaping up from behind rocks and bushes, and up out of shallow holes where they had hidden themselves.

'Ambush!' shouted Cador, and cursed, striking the ground with his sword.

Keldrych had hidden half of his warband in the glen and now they sprang to the attack – sixty in all, at least. The Pendragon was surrounded.

Gwenhwyvar ran to Medraut, plucked the spear from his chest and turned to stand beside her husband. They stood together to face the onslaught.

In the same instant, across the glen, a tremendous cry burst forth from fifty thousand throats as the hidden Picti rose up. Spears in hand, they stood on the hilltops, poised for attack, venting their hideous battle shriek. My skin pricked to hear it.

'Hurry!' I shouted at Cador. 'Sound the attack!'

Cador, his face grim and his jaw set, shook his head. 'I ' cannot. I am ordered to stand firm unless the Picti attack.'

'Look!' I flung my hand to the battle ground below. 'They attack!'

'I cannot!' Cador cried. 'I have my orders!'

They will be killed!'

'God knows!' Cador screamed. 'But unless the war host commits to battle, I can do nothing!'

I understood then. However things went between Medraut and the High King, Arthur had made Ban and Cador vow not to interfere. So long as the main force of Picti held back, the British would not provoke them. If there was to be war, the Pendragon's host would not begin it. As the main force of the enemy had not yet joined battle, Cador could do nothing.

In a fever of horror and rage, I turned back to the crooked glen. Arthur had unslung Prydwen and Gwenhwyvar now held it. The Picti were upon them, but the warriors of the Round Table, the Flight of Dragons, charged into the fray.

The renowned Dragons met the Picti just as they reached Arthur. I stood amazed at how masterfully the Britons engaged the enemy, divided them, and began turning the attack aside.

Cai and Bedwyr, riding side by side, drove in towards the centre of Keldrych's warband, their spears carrying the enemy before them. Gwalcmai and Gwalchavad struck in from the right, scattering the enemy as they thundered past. Bors, Llenlleawg and Rhys moved in from the left, hewing into the Picti, reapers at a bloody harvest.

In the churning mass of bodies, limbs and weapons, I saw the Pendragon's mighty sword Caliburnus rising and falling with relentless strokes, each blow a killing blow. The stream ran red; the water scarlet.

Any moment I expected to see the great Picti war host join Keldrych in the glen. But each time I stole a glance to the hills I saw them standing as before. What were they waiting for?