'They're refugees from time, Charles. Look around you-there are no clocks anywhere and almost no one wears a wristwatch.'

'Refugees? Yes… in some ways the place reminds me of the Third World. It's like a very up-market favela in Rio, or a luxury bidonville outside Algiers.'

'It's the fourth world, Charles. The one waiting to take over everything.'

We returned to the Porsche and cruised around the plaza. I watched the villas and apartment houses, hoping for the sound of a raised human voice, a too-loud stereo system, the recoil of a diving board, and realized that we were witnessing an intense inward migration. The residents of the Costasol complex, like those of the retirement pueblos along the coast, had retreated to their shaded lounges, their bunkers with a view, needing only that part of the external world that was distilled from the sky by their satellite dishes. Standing empty in the sun, the sports club and social centre, like the other amenities engineered into the complex by its Swiss consultants, resembled the props of an abandoned film production.

'Crawford, it's time to leave-let's get back to Estrella de Mar…'

'You've seen enough?'

'I want to hear that tennis machine of yours and the laughter of tipsy women. I want to hear Mrs Shand telling off the waiters at the Club Nautico – if she invests here she'll lose everything.'

'Maybe. Before we go we'll look in at the sports club. It's semi-derelict but it has possibilities.'

We passed the marina and turned into the forecourt of the sports club. A single car was parked by the entrance, but no one seemed to be present in the empty building. We stepped from the Porsche and strolled around the drained swimming pool, looking down at the canted floor that exposed its dusty tiles to the sun. A collection of hair-clips and wine glasses lay around the drainage vent, as if waiting for a stream to flow.

Crawford sat back in a chair by the open-air bar, watching me while I tested the spring of the diving board. Handsome and affable, he gazed at me in a generous but canny way, like a junior officer selecting a raw recruit for a sensitive mission.

'So, Charles…' he said when I joined him at the bar. 'I'm glad you came on the tour. You've just seen the promotional video presented to all new owners at the Residencia Costasol. Compelling stuff?'

'Absolutely. It's very, very strange. Even so, most visitors driving around wouldn't notice anything odd. Apart from this pool and those empty shops it's extremely well-maintained, there's excellent security and not a trace of graffiti anywhere – most people's idea of paradise today. What happened?'

'Nothing happened.' Crawford sat forward, speaking quietly as if not wanting to unsettle the silence. 'Two and a half thousand people moved in, mostly well-off and with all the time in the world to do the things they'd dreamed about in London and Manchester and Edinburgh. Time for bridge and tennis, for cordon bleu and flower-arrangement classes. Time for having little affairs and for messing about in boats, learning Spanish and playing the Tokyo stock market. They sell up and buy their dream house, move everything down to the Costa del Sol. And then what happens? The dream switches itself off. Why?'

'They're too old? Or too lazy to bother? Doing nothing may secretly be just what they wanted.'

'But that isn't what they wanted. Plot for plot, villa for villa, the Residencia Costasol is far more expensive than similar developments in Calahonda and Los Monteros. They paid a fat extra premium to have all these sports facilities and leisure clubs. Anyway, the people here are not that old. This isn't a geriatric ward. Most of them are the right side of fifty – they took early retirement, cashed in their share options or sold their partnerships, made the most of a golden handshake. The Costasol complex isn't Sunset City, Arizona.'

'I've been there. Actually, it's a lively spot. Those seventy-year-olds can get pretty frisky.'

'Frisky…' Wearily, Crawford pressed his palms against his forehead. He stared at the silent villas around the plaza, their shaded balconies waiting for nothing to happen. I was tempted to make another flippant remark, but I could see that he felt an almost impatient concern for the people of the Residencia. He reminded me of a young district commissioner in the days of Empire, faced with a rich but torpid tribe that inexplicably refused to leave its huts. The bandage on his arm had leaked a little blood on to his shirtsleeve, but he was clearly uninterested in himself, driven by a zeal that seemed so out of place in this land of jacuzzis and plunge-pools.

'Crawford…' Trying to reassure him, I said: 'Does it matter? If they want to doze their lives away with the sound turned down, let them…'

'No…' Crawford paused and then reached forward to grip my hand. 'It does matter. Charles, this is the way the world is going. You've seen the future and it doesn't work or play. The Costasols of this planet are spreading outwards. I've toured them in Florida and New Mexico. You should visit the Fontainebleau Sud complex outside Paris – it's a replica of this, ten times the size. The Residencia Costasol wasn't thrown together by some gimcrack developer; it was carefully planned to give people the chance of a better life. And what have they got? Brain-death 'Not brain-death, Bobby. That's Paula-speak. The Costa del Sol is the longest afternoon in the world, and they've decided to sleep through it.'

'You're right.' Crawford spoke softly, as if accepting my point. He took off his aviator glasses and stared at the harsh light reflected from the pool tiles. 'But I intend to wake them up. That's my job, Charles – why I was picked I don't know, but I stumbled on a way of saving people and bringing them back to life. I tried it at Estrella de Mar and it worked.'

'Perhaps. I'm not sure about that. But it won't work here. Estrella de Mar is a real place. It existed before you and Betty Shand arrived.'

'The Residencia Costasol is real. Too real.' Crawford doggedly recited his uncertain credo, rehearsing an argument that I guessed he had run through many times, an amalgam of alarmist best-sellers, Economist think-pieces and his own obsessive intuitions that he had put together on the windswept balcony of his apartment. 'Town-scapes are changing. The open-plan city belongs to the past-no more ramblas, no more pedestrian precincts, no more left banks and Latin quarters. We're moving into the age of security grilles and defensible space. As for living, our surveillance cameras can do that for us. People are locking their doors and switching off their nervous systems. I can free them, Charles. With your help. We can make a start here, in the Residencia Costasol.'

'Bobby…' I met his engaging, sea-blue eyes, fixed on me with their curious mix of threat and hope. 'There's nothing I can do. I came here to help Frank.'

'I know, and you have helped him. But now help me, Charles. I need someone to hold the fort for me, keep an eye on the ground and warn me if I'm going too far-the role Frank played at the Club Nautico.'

'Look… Bobby, I can't-'

'You can!' Crawford held my wrists and drew me towards him across the table. Behind his pleading was a strange missionary fervour that seemed to float across his mind like the malarial visions of that young district officer he so resembled, reaching out for the aid of a passing traveller. 'We may fail but it's worth trying. The Residencia Costasol is a prison, just as much as Zarzuella jail. We're building prisons all over the world and calling them luxury condos. The amazing thing is that the keys are all on the inside. I can help people to snap the locks and step out into real air again. Think, Charles-if it works you can write a book about it, a warning to the rest of the world.'

'The kind of warning that no one is keen to hear. What do you want me to do?'