And that was not all the bad news, though the rest was familiar enough. Beard had stripped to the waist and was now, resentfully, buttoning his shirt. The consulting rooms were on the nineteenth floor of a block in downtown El Paso, same floor, Beard remembered, that his mother had died on. Parks, whose people originally came from St Kitts, had minty breath and a wise old leathery face of silvery black. His head projected forward from his shoulders turtle fashion and bobbed kindly whenever Beard spoke. He was the same age as Beard, though some inches taller, and kept in shape by swimming, he said, every morning of the working week, between six and seven, before he saw his first patient. Beard could not imagine being wet, or even awake, at that time of day and knew he could never compete with this boast, could never pay the price of such inconvenience and discomfort to lower his body-mass index.

It was true, the doctor did not lecture or moralise, but he compensated with a disengaged, insulting frankness. With each instance, each looming physical catastrophe, the wise turtle head protruded a little further and he gently tapped his own palm with a pencil. No one, he said, not even Beard, would choose to walk around with a body like Beard's. He was carrying an extra sixty-five pounds, the equivalent of a combat infantryman's full pack. His knees and ankles were swollen from the weight, osteoarthritis was a growing possibility, his liver was enlarged, blood pressure was up again and there was a growing risk of congestive heart failure. His bad cholesterol was high, even by English standards. He was clearly experiencing breathing difficulties, he stood a decent chance of diabetes mellitus as well as advancing the likelihood of prostate and kidney cancer and thrombosis. His one piece of luck – luck, Beard noted, not virtue – was that he was not addicted to cigarettes, otherwise he might already be dead.

The doctor's head and shoulders were framed by a south-facing plate-glass window, a glaring rectangle of hazy white sky suggestive of the oppressive morning heat. Occasionally, an airplane drifted across, taking a turn around the city before landing on the east side. Over the river was Juarez, currently a world capital for murder as drug gangs fought their turf wars and slaughtered along the way soldiers, judges, policemen and city officials. Now the Mexican cartels were hiring unemployed Texan teenagers to do their killing. Clearly, life would push on without Michael Beard. As he listened to Parks enumerate his possible futures, he decided not to mention his recent acquisition of a classic symptom, the occasional sensation of tightness around his chest. It would only make him appear even more foolish and doomed. Nor could he admit that he did not have it in him to eat and drink less, that exercise was a fantasy. He could not command his body to do it, he had no will for it. He would rather die than take up jogging or prance to funky music in a church hall with other tracksuited deadbeats.

When Beard made his vague promise to return within the month, Doctor Parks was for tying him down to dates. Tuesday the twenty-third or Thursday the twenty-fifth, he must take his pick. Beard hesitated, Parks insisted, as though it were his own bloodstream through which liberated cancer cells were about to drift, looking for a new place, a nearby lymph node, to set up home. Beard chose the remoter date, knowing that he could phone Parks's secretary and blamelessly cancel.

Now, as Hammer ceased his terrible whistling and slowed to pass through the minute township of Cotton City, the sanctuary of an obscure clinic in Dallas looked more attractive. But Beard knew that he did not have the strength to run away. The arrangements for tomorrow had a momentum he could not interrupt, not when he was so hungry for public triumph, for that time in the early evening when little Lordsburg with its neon and burger joints and abundant air conditioning became nominally carbon neutral, and American civilisation, which stood for the aspirations of all the world, could continue on its way without the inconvenience of overheating. The eight-year journey from the slow deciphering of the Aldous file to lab work, refinements, breakthroughs, drawings, field tests must be completed. General acclaim was the final stage. Tarpin could do his worst.

Beard fiddled with the radio to catch the on-the-hour news, and there it was, a snappy interview with one of Hammer's PR team explaining that sunlight and water would first power Lordsburg and, one day, the entire planet.

Hammer whooped. 'Beautiful! I trained that girl up well.'

He and Beard never acknowledged, not even to each other in private, that they would not really be supplying electricity to Lordsburg at all. They would be selling kilowatt hours to a local utility company that were the rough equivalent of the town's average consumption over a year. The electrons from their revolutionary plant would swarm anonymously among the rest.

'We'll all be down there,' the announcer said. 'Out on Highway 90, three miles east of 70. Join us at 6 p.m. tomorrow, countdown to switch-on, when Lordsburg leads the world!'

Soon they were heading east on the interstate, and then swinging north round the town and after a couple of miles turning right for Silver City. Minutes later they came over a slight rise that gave them a view of the site. Beard had seen it many times in the past months, with everything in place and dry runs going smoothly after some initial setbacks. But still, this afternoon he felt a little swoon of pride. Sensing the mood, Hammer slowed.

'Well, matey,' he said, concealing his own strong emotions behind a hideous attempt at cockney. 'Don't it just warm the cockles of your 'eart?'

The twenty-three big tilted panels had a dull gleam under the ferocious sun. They were fed by a mess of pipework and valves. Behind them were the storage tanks for the compressed hydrogen and oxygen, and alongside were the breezeblock sheds housing the fuel-cell generator and the catalysts. Power lines on new poles led to the nearest of the ancient wooden pylons that tottered in succession across the immensity of semi-desert. On the other side of the tanks was a pumping station built over the deep water source, and beyond was a neat brick building that housed the computers.

What was new were the hundreds of people, construction workers, vendors and sound technicians, moving importantly between tasks, and the many hundreds or thousands of Stars and Stripes planted on poles around the panels where the security fence should have been, and in triangular bunting along the top of the giant pale blue marquee and down its guy ropes, around the sound stage, and lining the recently bulldozed half-acre square where the army band would march, and suspended in artfully drooping streamers over the bleachers where the local VIPs would sit, and along the avenue formed by fast-food and cold-drink concessions and, at right angles to it, down an even grander avenue of portable lavatories, and around the perimeter of the parking lot, where there were at least a hundred vehicles instead of the usual dozen, with room for a couple of thousand more. Not a single Union Jack, Beard noted moodily, to honour himself, the inventor and first mover of the project. But he said nothing, and banished the thought.

To one side, on another space cleared of vegetation, and unadorned by flags, were media trucks and satellite dishes. A few hundred yards out into the scrub, on a low rise parallel to the highway, was the unlit neon 'Lordsburg!' sign, in homage to the lettering of the famous Hollywood landmark, all characters erected except the exclamation mark, and even now this thirty-foot-high punctuation was being hauled upright with ropes by men in hardhats.

As they turned off the road onto a dirt track and passed under a proscenium of yet more Stars and Stripes, an aroma of frying fat, chilled by the car's air conditioning, filled the cabin and tickled their noses.