It was dark by the time they had managed to pull the mirror out. They hunkered down beside it and shone their flashlights on it. The decorative vine-tendrils had been badly bent by the towing-chains, but there was no other obvious damage. The surface of the mirror was black and mottled, like a serious bruise, but otherwise it seemed to have survived its seven hundred years with very little corrosion. It was 22cm wide and 57cm high, and it was over 3cm thick. It was so heavy that they could barely lift it.

"What do we do now?" asked Katie.

"We clean it up. Then we talk to one or two dealers, and see how much we can get for it."

"But what about Shalott?" asked Nigel. "This island - it's all going to be lost."

"That's the story of Britain, Nigel. Nothing you can do can change it."

They heaved the mirror into the back of the Range Rover and drove back into Wincanton. Mark had rented a small end-of-terrace house on the outskirts, because it was much cheaper than staying in a hotel for seven weeks. The house was plain, flat-fronted, and painted a dirty pink. In the back garden stood a single naked cherry-tree.

Between them, grunting, they maneuvered the mirror into the living-room and propped it against the wall.

"I feel like a criminal," said Nigel.

Mark lit the gas fire and briskly chafed his hands. "You shouldn't. You should feel like an Englishman, protecting his heritage."

That evening, Mark ordered a takeaway curry from the Wincanton Tandoori in the High Street, and they ate chicken Madras and mushroom bhaji while they took it in turns to clean away seven centuries of tarnish.

Neil played The Best of Matt Monroe on his CD player. "I'm sorry... I didn't bring any of my madrigals."

"Don't apologize. This is almost medieval."

First of all, they washed down the mirror with warm soapy water. Then Katie stood on a kitchen chair and cleaned all of the decorative detail at the top of the frame with a toothbrush and cotton-buds. As she worried the mud out of the human head in the center of the mirror, it gradually emerged as a woman, with high cheekbones and slanted eyes and her hair looped up in elaborate braids. Underneath her chin there was a scroll with the single word "Lamia".

"Lamia!" said Nigel. "That's the Greek name for Lilith, who was Adam's first companion, before Eve. She demanded the same rights as Adam and so God banished her Eden. She married a demon and became the queen of demons.

He touched the woman's faintly-smiling lips. "Lamia was supposed to be the most incredibly irresistible woman you could imagine. Just one night with Lamia and pfff! - you would never look at a human woman again."

"What was the catch?"

"She sucked all of the blood out of you, that's all."

"You're talking about my ex again."

Katie said, "John Keats wrote a poem called Lamia, didn't he?"

"That's right," said Nigel. "A chap called Lycius met Lamia and fell madly in love with her. The trouble is, he didn't realize she was cursed by God. 'Some penanced lady-elf... some demon's mistress, or the demon's self.'"

"Cursed," said Katie. "Like the Lady of Shalott. Perhaps they were one and the same person."

There was no question that the woman's face on the mirror was beautiful; but it had a slyness about it, too.

"Lamia was a bit of a mystery, really," said Nigel. "She was a blood-sucking enchantress, but she was capable of deep and genuine love. Lycius said she gave him 'a hundred thirsts.'"

"Just like this chicken Madras," said Mark. "Is there any more beer in the fridge?"

Katie carried on cleaning the mirror long after Mark and Nigel had grown tired of it. They sat in two reproduction armchairs drinking lager and eating cheese-and-onion crisps, watching while Katie gradually exposed a circle of shining silver, large enough to see her own face.

"There," she said. "It's amazing, isn't it, to think that the last person to look into this mirror could have been the Lady of Shalott?"

They didn't go to bed until well past one am. Mark had the main bedroom because he was the boss, while Katie had the child's bedroom at the back, with teddy-bear wallpaper, and Nigel had to doss down on the sofa in the living-room.

Mark slept badly that night. He dreamed that he was walking at the rear of a long funeral procession, with a horse-drawn hearse. A woman's voice was calling him from very far away, and he stopped, while the funeral procession carried on. "Mark!" she kept calling him. "Mark!"

"Mark!" she screamed. It was Katie, calling him from downstairs, and her voice was filled with panic.

He rolled out of bed, still stunned from sleeping. and stumbled down the narrow staircase. In the living-room the curtains were drawn back, although the grey November day was still dark, and it was raining. Katie was standing in the middle of the room in her pink cotton nightshirt, her hair standing up like a fright wig.

"Katie! What the hell's going on?"

"It's Nigel! I called him but he didn't answer! Mark, he's all wet! Something's happened to him!"

Mark switched on the overhead light. At first he couldn't understand what he was looking at. But then Katie made an extraordinary mewling noise, and he realized that he was looking at Nigel.

Nigel was lying on his back on the couch, wearing nothing but green woollen socks and a faded blue underpants. He was staring up at the ceiling, wide-eyed, his mouth stretched wide open, as if he were shouting at somebody. There was no doubt that he was dead. His throat had been torn open, in a stringy red mess of tendons and cartilage, and the cushion beneath his head was soaked black with blood.