But the pilot had a second target in his sights. When he was four hundred yards away he raised an arm over his windscreen and fired a signal flare from the open cockpit. The flare rose into the air, hovered above the refreshment tent and exploded in a globe of emerald light. It hung in the sky like a melting chandelier, and then fell into the car park, its green embers setting fire to the grass.

Already the first guests were rising from their seats, suspecting that this aerial display was not part of the official programme. Men buttoned their jackets as wives held their hats, coughing when fumes from the flare drifted through the marquee. A grim-faced Alain Delage, once again the harassed accountant, was calling to his aides, who sprang to life and began shouting into their mobile phones.

The pilot changed course, banked his wings and began a circuit of the site. Caught by the crosswind, his green banner had wrapped itself into a knot, turning the lettered slogan into an unreadable Moebius strip.

'Is that it?' Penrose made a two-fingered salute to the pilot. 'Not much of a show.'

'He hasn't got your resources. Wait, though…' I pointed to the fir-topped hills. The drone of competing engines made its Doppler run towards us. Three more publicity planes sped down the valley, towing their pennants and followed by a straggler who had joined the fly-past at late notice. I guessed that the pilots had joined the protest in a show of solidarity, leaving their allotted circuits of the Côte d'Azur to rendezvous above Sophia-Antipolis.

They flew towards us, shadows crossing the canvas roof above our heads, engines drumming against the hulls of the graders and bulldozers. The metal scoops amplified the mushy drone, a muffled anthem played by an involuntary steel band. Banners fluttered across the air, advertising a supermarket in Le Cannet, a kitchenware store and a sale of demonstration Renaults in Cagnes-sur-Mer. They crossed the D103 and set off for their beach patrols, rolling their wings in farewell.

The pilot with the green pennant circled the site, waiting until his companions had gone. A passenger sat in the open cockpit behind him, and as the sun struck the windscreen I caught a glimpse of blonde hair under an antique helmet and goggles.

Satisfied, the pilot banked steeply and climbed into the sun, his wings shedding light into the air.

Groups of guests walked to their cars, while others sat among the overturned chairs. Olivier Destivelle stood by the plaque, pointing to the empty sky with his silver trowel. Alain Delage spoke to a senior police officer, but his men were distracted by the limousines jamming the car-park exits, horns blaring at each other.

'A slight cock-up…' Penrose swung his gilt chair in his hand, as if debating whether to climb into the sky. 'So much for security. Did you catch the slogan?'

'Used Renaults, a supermarket somewhere. Quite a threat.'

'Paul, be serious for once.' Penrose tried to wave away the pall of burnt aviation fuel. 'The pilot with the flare pistol. He was the organizer.'

'"Eden II – Extinction is For Ever." Mean anything?'

'Green nonsense.' Penrose shrugged and stared back at the sky, but I could see he was nettled. 'Still, the pilot made his point. Progress has been held back by a microsecond. A shame, though. It's an important day.'

Forgetting me, he set off for the refreshment tent. A few journalists were picking at the buffet tables as they spoke into their cassette recorders, but the television crews were climbing into their vans, ready to relay their footage to the evening news programmes.

Penrose listened to the last drone of the aircraft echoing through the valleys towards the coast. Barely able to control his irritation, he sucked the meat from a lobster claw. 'Paul, what sort of aircraft was it? Someone should have jotted down the registration number.'

'A Czech air force basic trainer. Slow, but fun to fly.'

'I bet. You recognized the pilot.'

'Four hundred yards away? Pilots don't sign their slipstreams.'

'I thought they did. Frances Baring may know him. She's chummy with the rodeo pilots at Cannes Airport.' Penrose held a smoked salmon fillet to his nose, smelling the pink flesh. 'You understand her, Paul. I'd hate to think she was involved in this nonsense.'

'She isn't. Wilder, she works hard for Eden-Olympia.'

'Everyone works hard – it proves nothing. People are impressionable, they snatch powerful emotions out of the air. The one thing Eden-Olympia doesn't need is its own Green movement. Why doesn't anyone want to save the planet's concrete?'

'I guess it can look after itself.'

'Can it?' Penrose turned to stare at me, as if I had conveyed a unique insight. He swallowed the canapé, took the glass of wine from my hand and gulped it back. 'Right, that was lunch. Let's go for a drive above Grasse. I need the high air to think in…'

The first signs of revolt had appeared, but not in a way that Wilder Penrose expected. As we set off for Grasse he watched the rearview mirror, suspicious of any following cars. The pinpricks of the past weeks – the graffiti and vandalized cars in the Eden-Olympia garages – had begun to penetrate even the well-upholstered hide of the corporate elephant.

It was a pleasure to see Penrose in the role of quarry, for once.

As Frances had predicted, the ratissages had grown more violent, but sooner or later the victims would turn on their attackers. One evening, in an immigrant neighbourhood, the residents would at last act together, corner a therapy class of senior executives and hold them until the television cameras arrived. Then the conspiracy would collapse and witnesses would come forward: the chauffeurs' widows, the girls at the refuge, brutalized whores and assaulted Arab workmen.

Yet, despite myself, I still admired Penrose, and the core truth of his bold but deranged vision. I hated the violence but remembered the brutal hazings at the RAF flight school, and how they had energized us all. Those fraternal beatings had been the closest we would ever come to tormenting our prisoners, part of the cruel but necessary pleasures of war. At Eden-Olympia, psychopathy was being rehabilitated, returned like a socialized criminal to everyday life.

For all his success, Penrose had been on edge in the two months since Zander's death. Often he knocked over his chesspieces as we played beside the pool. In the middle of a move he would leave the table and pace alone around the tennis court, then walk to his car without a word. At times he seemed to doubt that he was equal to the huge test of his talents posed by Eden II, and was searching for an even more radical leap of faith.

As we climbed the mountains above Grasse he patted my arm, treating me to the conspiratorial smile he turned upon waitresses and filling-station personnel who met his approval. He pointed to the rev counter, trembling in the red zone. 'Feel the power, Paul? When I'm bored you can take over.'

'As long as you're in control.'

'Who wants to be in control? Haven't I taught you anything?' He drummed a hand on the wheel. 'Those publicity planes – they spoilt the show.'

'No one noticed. They were glad to get back to the office. A kitchenware sale, some clapped-out cars…'

'You're wrong, Paul.' Penrose pointed to a billboard advertising a new hair spray. 'That's just the point. Reality is always a threat. I'm not worried by any rival ideology – there isn't one. But all these ads for aquaparks and swimming pools… they're the real enemy. They subvert everything. Frances probably arranged it deliberately.'

'Why should she?'

'To unsettle me. She's restless. You know that, Paul. She thinks she's a rebel, but doesn't realize that Eden-Olympia is the biggest rebellion of all.'

Frances would disapprove of my accepting a lift in Penrose's car. We met rarely now, and she said nothing of her plans to expose Eden-Olympia. Our hour together near the lighthouse at La Garoupe had been a closing of accounts. She had tried to use me again, hoping to trigger an outburst against Eden-Olympia, but I was too uncommitted for her. We met for dinner at the Vieux Port, and I told her that I was working my way into Penrose's confidence. She nodded, lit a cigarette and stared at the Arab yachts.