Then Mark looked more closely. A streak of red had stained the canary yellow paintwork of the front stem and left rust-like spots on the spokes. He shivered with misgiving and fingered the radio in his pocket. Suddenly he wished he hadn’t come out alone, after all. There was no reassuring presence alongside him, no Owen there to know exactly what to do.

With a shaking hand, Mark made a note of the colour, model and number of the bike, crumpling the pages of his notebook in his haste to get it out of his pocket. The act of writing made him feel better, more in control, as if the ink marks on the page had magically brought a familiar voice from the air: ‘Observe, keep a note, report back.’

‘Yes, Owen,’ whispered Mark.

Feeling the sweat drying on his forehead and the back of his neck, he forced himself to walk past the bike to where the stones were clustered among the spindly birches. Somebody had lit a fire here recently, leaving scorched earth and a pile of white ash. People were always lighting fires near the Virgins, as if they thought the flames might melt their stony hearts. At the midsummer solstice, there were hundreds of folk up here at night, and they did a lot more than light fires.

Mark stopped abruptly as he looked into the circle. The sensations that came reminded him of the terrors of his puberty, the physical sickness and the guilt. He tried to concentrate on studying the ground, to look for evidence of bike tracks or footprints. He tried to think about casting around for telltale objects that might have been dropped by someone who had been in the area. I’m observing, he told himself. I must observe. Be professional and calm, and don’t rush into anything.

But he couldn’t keep up the pretence for long. His eyes just wouldn’t focus on anything else. With shameful fascination, Mark found his attention drawn to the centre of the stone circle, where the white shape lay in such startling, rousing incongruity.

‘Oh, Jesus.’

The body of the woman sprawled obscenely among the stones. Her half-naked torso had been flung on the rough grass, her arms and legs twisted in provocative gestures. Her right knee was lifted high, to the level of her waist, and her left leg was stretched taut, as if she might be about to spring into the air.

Mark could see every detail of the muscles in her legs, the tendons rigid under the skin at the top of her thigh, the faint crinkling of cellulite on her hips. Her pose was a caricature of life, a cruel parody of flamboyance and movement. Her hands were tilted at the wrist, her toes pointed downwards, and her head nodded to silent music. She was spread against the ground in a final arabesque, in a fatal pirouette, or the last fling of an abandoned tango.