A cloud of butterflies rose into the sunlight, the breeze smeared them across the summer sky and a hundred thousand young faces shining with wonder turned upwards to watch them drift overhead.

In the forefront of that vast concourse sat a girl, the girl that he had been stalking for ten days now. A hunter studying his prey, he had come to know with a peculiar intimacy her every gesture and movement, the turn and lift of her head as something caught her attention, the way she cocked it to listen, or tossed it in annoyance or impatience. Now in a new attitude she lifted her face to the glorious cloud of winged insects, and even at this distance he could see the sparkle of her teeth, and her lips formed a soft pink 'O' of wonder.

On the high stage above her the figure in the white satin shirt held up yet another box and, laughing, shook from it a fresh burst of fluttering wings. Yellow and white and iridescent, they bore aloft, and the crowd gasped and 'oohed' afresh.

One of the butterflies toppled and dived; and, though a hundred hands were held out to catch it, it swerved and wobbled down to alight at last on the girl's upturned face. Even above the swelling murmur of the crowd, he heard the girl's happy cry of laughter, and he found himself smiling in sympathy with her.

She reached up to where it sat on her forehead and took it gently, almost reverently, in the cup of her hands. For a moment she held it close to her face, studying it with those indigo-blue eyes that he had come to know so well. Her expression was suddenly wistful, and her lips moved as she whispered to it, but he could not hear the words.

Her sadness was fleeting, and then those lovely lips smiled again and she leapt to her feet and held both hands high above her head, standing on tiptoe. The butterfly hesitated, perched on her outstretched fingertips, pulsing its wings softly on the point of flight, and he heard her voice.

'Fly! Fly for me!' And those around her took up the cry.

'Fly! Fly for peace!'

For a moment she had usurped the limelight, and all eyes were fastened on her rather than on the flamboyant single figure in the centre of the stage. She was tall and lithe, her bare limbs tanned and glowing with health. She wore her skirt so short, in the fashion of the day, that as she reached upwards the hem rose high above the circular creases where her cocky little buttocks joined her thighs in a froth of white lace.

For a moment, poised like that, she seemed to epitomize her generation, wild and free and fey, and he sensed the instant accord of spirit of all those who watched her. Even the man on the stage leant forward to see her better, and his lips, thick and livid as though stung by bees, split in a smile and he called out: 'Peace!' And his voice was magnified a thousand times by the great banks of amplifiers that rose high on each side of the stage.

The butterfly flew from her hands, and she pressed all her fingers to her lips and blew a wide kiss after it as it fluttered aloft and was lost in the swirling cloud of insects. The girl sank down on to the grass, and those seated close to her reached out to touch and embrace her.

On the stage Mick Jagger held his arms wide, commanding silence. Once he had it, he spoke into the microphone. Distorted by the amplifiers, his voice was slurred and incoherent; his accent so thick that the watcher could barely understand the stumbling tribute he read out to the member of his band, who only days previously had drowned in a swimming-pool during a wild weekend party.

The whisper was that the victim had been almost comatose with drugs when he entered the water. It was a hero's death, for this was the age of drugs and sexual excess, of pot and Pill, of freedom and peace and overdosing.

Jagger ended his little speech. It had been so brief that it had not dulled the buoyant mood of the gathering. The electric guitars struck a discord, and Jagger hurled himself into 'Honky Tonk Woman' with every fibre of his being. Within seconds he had a hundred thousand hearts racing in time to his, a hundred thousand young bodies jerking and pulsing, and two hundred thousand arms held high, swaying like a field of wheat in a high wind.

The music was cosmic, brutal as an artillery bombardment; painful to the ear, it penetrated the skull and seemed to numb and crush the brain. Swiftly it reduced the audience to a mindless frenzy, transformed the multitude into a single organism, like a gigantic amoeba that throbbed and undulated in the act of reproduction, fraught with a passion that was overtly sexual; and from it rose the stench of dust and sweat, the sickly odour of cannabis smoke and the heady overpowering musk of young bodies physically aroused.

The watcher was alone in the midst of the throng, isolated and detached, unmoved by the blasts of sound that swept over him. He studied the girl, awaiting his moment.

She swayed to the primeval rhythm, moved in time to the bodies that pressed close about her, but with a singular grace that set her apart. Her hair was glistening jet with highlights of ruby that glinted in the sun, piled on top of her head; but thick tresses of it had come down in smoky coils, enhancing the elegant line of her neck and the set of her head upon it, like a tulip on its stem.

Directly below the stage, an area had been cordoned off with a low picket fence, a tiny enclave for a privileged few. Marianne Faithfull, in a flowing caftan but with bare feet, sat here with the other wives and camp-followers. Her beauty was remote and ethereal. Her eyes seemed dreamy and sight-less as those of a blind woman, and her movements slow and somnolent. Children crawled about her feet, and they were guarded and protected by a phalanx of Hell's Angels.

In black Wehrmacht steel helmets, hung with chains and Nazi iron crosses, chest hair curling out from under gilets of black leather studded with silver metal, steel-shod motor-cycle boots, arms covered with intricate tattoos, they struck menacing poses, arms akimbo, billy-clubs in their belts, and their clenched fists heavy with sharp-edged steel rings. They surveyed the crowd with brooding insolent stares, watching for trouble, hoping for trouble.

The music pounded on and on, an hour and then another, the heat built up, and the smell of humanity was like that of an animal-cage, for some of the audience, both men and women, hemmed in and reluctant to miss a moment of it, had urinated where they sat.

The watcher was disgusted by the decadence, by the wild abandon and the gross indulgence of it all. It offended every-thing that he believed in. His eyes felt gritty and sensitive, and his head ached, throbbing in time to the driving rhythm of the guitars. It was time to leave. Another day wasted, another day spent waiting for the opportunity that never came. However, he was a hunter with all the patience of the predator. There would be other days; he was in no hurry. The moment must be exactly right for his purpose.

He began to move, working his way across the low knoll where he had stood through the dense throng of bodies, shouldering through them; they were in such a mesmeric trance that they seemed neither to see nor to feel him push past them.

He glanced back, and his eyes narrowed as he saw the girl speak to the boy beside her, smile and shake her head in response to his reply and rise to her feet. Then she also began to work her way through the crowd, stepping over the seated ranks, steadying herself with a hand on a shoulder, laughing an apology as she went.

The watcher changed direction, angling down the gentle slope to intercept her, the hunter's instinct warning him that unexpectedly the moment for which he had waited had arrived.

Behind the stage were the television-trucks, row upon row of them, each as tall as a double-decker bus, parked so close together that there were only inches between them.

The girl moved back, circling the low picket fence, working her way around the side of the stage trying to get clear of the throng; but it was so dense that it blocked her further progress, and her expression was desperate as she glanced around her, caught in the press of bodies.

Suddenly she turned directly towards the fence, pushed her way to it, and then with a swift athletic bound jumped over it and scuttled into the narrow space between two of the high television-trucks. One of the Hell's Angels saw her dart away into the forbidden area, and he shouted and followed her at a run, twisting his shoulders to squeeze into the narrow passage down which she had disappeared; and, as he turned, the watcher had a flash of the grin on his face.

It took the watcher almost two minutes to force his way to the point on the fence where the girl had crossed. Somebody reached out to stop him, but he struck the hand away and went over it, and slipped into the space between the high steel sides of the parked trucks.

He moved sideways, the gap too narrow to accommodate the width of his shoulders, and he was level with the door of the driver's cab when he heard the muffled cries of protest just ahead of him. The sound spurred him, and as he came around the side of the bonnet, he checked for an instant as he took in what was happening just in front of him.

The Hell's Angel had caught the girl, and now he had her held against the front wing of the truck. He had one of her arms twisted up behind her back, at almost the level of her shoulder-blades. She was facing him, but he pressed her backwards against the steel wing with his hips and his pot belly. He bent over her, trying to reach her mouth with his. The girl's back was arched, and she rolled her head violently from side to side trying to avoid his mouth. He was laughing, his mouth wide open, flicking his tongue out at her, trying to force it into her mouth.

With his right hand he had hoisted the tiny skirt up to her waist, and his hairy fingers, stained with motor-cycle grease, were hooked into the waistband of her lace panties. The girl was striking and clawing at him with her free hand, but he hunched his shoulders so that she could not reach his face with her nails, and her blows fell on studded black leather and on thick shoulders padded with muscle and fat. The Angel's laughter was thick and guttural, and the lace of her panties tore with a sharp crackling sound as he forced them over her hips and down the smooth tanned thighs.

The watcher stepped forward and touched the Angel's shoulder, and the man froze and twisted his head round. His eyes were glazed, but they cleared instantly and he flung the girl sideways so viciously that she sprawled on the torn muddy grass between the trucks. The Angel reached for the club in his belt.

The watcher reached out and touched him again, under the ear, just below the rim of his steel helmet. He pressed with two fingers, and the Angel froze and stiffened; all his limbs went rigid, and he made a glottal cawing sound deep in his throat, his entire body convulsed and he collapsed in a heap and, like an epileptic, lay twitching and jerking spasmodically. The girl was on her knees, pulling up her torn underclothes, and watching in fascinated horror. The watcher stepped over the sprawling Angel and lifted the girl to her feet without apparent effort.

'Come,' he said softly. 'Before his friends arrive.' Swiftly he led her away by the hand, and she followed as trustingly as a child.

Beyond the parked trucks was a maze of narrow path-ways through the rhododendron bushes. As they ran down one of these paths, she asked breathlessly: 'Did you kill him?'

'No.' He did not even glance round. 'He'll be on his feet again in less than five minutes.'

'You flattened him. How did you do that? You hardly touched him.'

He did not answer, but round the next bend in the path he stopped and turned back to face her. 'Are you all right?' he asked, and she nodded jerkily without speaking.

He studied her, still holding her hand. He knew she was twenty-four years old, a young woman who had just experienced a violent attempted rape, but the gaze of her dark blue eyes was level and appraising. There were no tears, no hysterics, not even a tremor of those pink lips, and the hand in his was slim and firm and warm.

The psychiatrist's report on her which he had studied had been correct in at least this much: she was resilient and self-assured; already she was almost fully recovered from the attack. Then he saw the colour mount softly in her cheeks and at the base of her long elegant throat, and her breath quickened perceptibly. She was experiencing another strong emotion.

'What's your name?' she asked, her eyes fastened on his with an intensity which he recognized. Women, on first encounter, usually looked at him like that.

'Ramón,' he replied. she repeated softly, relishing the sound of it. God, he was beautiful.

'Who?'

'You won't believe it if I tell you.' His English was perfect, too perfect. He must be foreign, but the voice matched his face, beautiful, deep and grave.

'Try me,' she invited, and heard the catch in her own voice.

'Ramón de Santiago y Machado.' He made it sound like music; it was impossibly romantic. It was the most beautiful name she had ever heard, perfect for that face and voice.

'We must go,' he said, while she still stared at him.

'I can't run,' she said. 'Don't make me run.'

'If you don't, you might end up as a mascot on the handlebars of a motor-cycle.' She laughed, and then bit her lower lip to stop herself. 'Don't do that,' she protested. 'Don't make me laugh. I need the loo. My condition is critical.'

'Ah, so that's where you were headed when Prince Charming fell in love with you.'

'I warned you, don't do that.'

With an effort she smothered her giggle, and he took pity on her. 'There is a public loo at the gate to the park. Can you make it that far?'

'I don't know.'

'The alternative is the rhododendrons.'

'No, thanks. No more public performances today.'

'Let's go, then.' He took her arm.

They skirted the Serpentine, and Ramón glanced back. 'Your boyfriend's ardour must have cooled.' he said. 'No sign of him. What a fickle fellow.'

'Pity. I'd love to watch you do that trick of yours again. How much further is it?'

'Here it is.' They had reached the gate, and she dropped his arm and started for the small red-brick building that nestled discreetly in the shrubbery beside the path; but at the door she hesitated.

'My name is Isabella, Isabella Courtney, but my friends call me Bella,' she said over her shoulder, and darted through the doorway.

'Yes,' he murmured softly, 'I know.'