‘I think you’ll be safe here, Lady,’ I said.

‘Tell me why you think that?’ she demanded sharply.

I took a moment to collect my thoughts. ‘When the Saxons come,’ I said, ‘they’ll advance along the Thames valley. Their aim is to reach the Severn Sea and that is their quickest route.’

Guinevere shook her head. ‘Aelle’s army will come along the Thames, Derfel, but Cerdic will attack in the south and hook up north to join Aelle. He’ll come through here.’

‘Arthur says not,’ I insisted. ‘He believes they don’t trust each other, so they’ll want to stay close together to guard against treachery.’

Guinevere dismissed that with another abrupt shake of her head. ‘Aelle and Cerdic aren’t fools, Derfel. They know they have to trust each other long enough to win. After that they can fall out, but not before. How many men will they bring?’

‘We think two thousand, maybe two and a half.’

She nodded. ‘The first attack will be on the Thames, and that will be large enough to make you think it is their main attack. And once Arthur has gathered his forces to oppose that army, Cerdic will march in the south. He’ll run wild, Derfel, and Arthur will have to send men to oppose him, and when he does, Aelle will attack the rest.’

‘Unless Arthur lets Cerdic run wild,’ I said, not believing her forecast for a moment.

‘He could do that,’ she agreed, ‘but if he does then Ynys Wydryn will be in Saxon hands and I do not want to be here when that happens. If he won’t release me, then beg him to imprison me in Glevum.’

I hesitated. I saw no reason not to pass on her request to Arthur, but I wanted to make certain that she was sincere. ‘If Cerdic does come this way, Lady,’ I ventured, ‘he’s liable to bring friends of yours in his army.’

She gave me a murderous look. She held it for a long time before speaking. ‘I have no friends in Lloegyr,’ she said at last, icily.

I hesitated, then decided to forge on. ‘I saw Cerdic not two months ago,’ I said, ‘and Lancelot was in his company.’

I had never mentioned Lancelot’s name to her before and her head jerked as though I had struck her. ‘What are you saying, Derfel?’ she asked softly.

‘I am saying, Lady, that Lancelot will come here in the spring. I am suggesting, Lady, that Cerdic will make him lord of this land.’

She closed her eyes and for a few seconds I was not certain whether she was laughing or crying. Then I saw it was laughter that had made her shudder. ‘You are a fool,’ she said, looking at me again. ‘You’re trying to help me! Do you think I love Lancelot?’

‘You wanted him to be King,’ I said.