Soon after three o'clock on the afternoon of April 22nd 1973, a 35-year-old architect named Robert Maitland was driving down the high-speed exit lane of the Westway interchange in central London. Six hundred yards from the junction with the newly built spur of the M4 motorway, when the Jaguar had already passed the 70 m.p.h. speed limit, a blow-out collapsed the front nearside tyre. The exploding air reflected from the concrete parapet seemed to detonate inside Robert Maitland's skull. During the few seconds before his crash he clutched at the whiplashing spokes of the steering wheel, dazed by the impact of the chromium window pillar against his head. The car veered from side to side across the empty traffic lanes, jerking his hands like a puppet's. The shredding tyre laid a black diagonal stroke across the white marker lines that followed the long curve of the motorway embankment. Out of control, the car burst through the palisade of pinewood trestles that formed a temporary barrier along the edge of the road. Leaving the hard shoulder, the car plunged down the grass slope of the embankment. Thirty yards ahead, it came to a halt against the rusting chassis of an overturned taxi. Barely injured by this violent tangent that had grazed his life, Robert Maitland lay across his steering wheel, his jacket and trousers studded with windshield fragments like a suit of lights.

In these first minutes as he recovered, Robert Maitland could remember little more of the crash than the sound of the exploding tyre, the swerving sunlight as the car emerged from the tunnel of an overpass, and the shattered windshield stinging his face. The sequence of violent events only micro-seconds in duration had opened and closed behind him like a vent of hell.

'… my God…'

Maitland listened to himself, recognizing the faint whisper. His hands still rested on the cracked spokes of the steering wheel, fingers splayed out nervelessly as if they had been dissected. He pressed his palms against the rim of the wheel, and pushed himself upright. The car had come to rest on sloping ground, surrounded by nettles and wild grass that grew waist-high outside the windows.

Steam hissed and spurted from the crushed radiator of the car, spitting out drops of rusty water. A hollow roaring sounded from the engine, a mechanical death-rattle.

Maitland stared into the steering well below the instrument panel, aware of the awkward posture of his legs. His feet lay among the pedals as if they had been hurriedly propped there by the mysterious demolition squad which had arranged the accident.

He moved his legs, reassured as they took up their usual position on either side of the steering column. The pedal pressure responded to the balls of his feet. Maitland ignored the grass and the motorway outside and began a careful inventory of his body. He tested his thighs and abdomen, brushed the fragments of windshield glass from his jacket and pressed his rib-cage, exploring the bones for any sign of fracture.

In the driving mirror he examined his head. A triangular bruise like the blade of a trowel marked his right temple. His forehead was covered with flecks of dirt and oil carried into the car by the breaking windshield. Maitland squeezed his face, trying to massage some expression into the pallid skin and musculature. His heavy jaw and hard cheeks were drained of all blood. The eyes staring back at him from the mirror were blank and unresponsive, as if he were looking at a psychotic twin brother.

Why had he driven so fast? He had left his office in Marylebone at three o'clock, intending to avoid the rush-hour traffic, and had ample time to cruise along in safety. He remembered swerving into the central drum of the Westway interchange, and pressing on towards the tunnel of the overpass. He could still hear the tyres as they beat along the concrete verge, boiling off a slipstream of dust and cigarette packets. As the car emerged from the vault of the tunnel the April sunlight had rainbowed across the windshield, momentarily blinding him…

His seat belt, rarely worn, hung from its pinion by his shoulder. As Maitland frankly recognized, he invariably drove well above the speed limit. Once inside a car some rogue gene, a strain of rashness, overran the rest of his usually cautious and clear-minded character. Today, speeding along the motorway when he was already tired after a three-day conference, preoccupied by the slight duplicity involved in seeing his wife so soon after a week spent with Helen Fairfax, he had almost wilfully devised the crash, perhaps as some bizarre kind of rationalization.

Shaking his head at himself, Maitland knocked out the last of the windshield with his hand. In front of him was the rusting chassis of the overturned taxi into which the Jaguar had slammed. Half hidden by the nettles, several other wrecks lay nearby, stripped of their tyres and chromium trim, rusty doors leaning open.

Maitland stepped from the Jaguar and stood in the waist-high grass. As he steadied himself against the roof the hot cellulose stung his hand. Shielded by the high embankment, the still air was heated by the afternoon sun. A few cars moved along the motorway, their roofs visible above the balustrade. A line of deep ruts, like the incisions of a giant scalpel, had been scored by the Jaguar in the packed earth of the embankment, marking the point where he had left the road a hundred feet from the overpass tunnel. This section of the motorway and its slip roads to the west of the interchange had been opened to traffic only two months earlier, and lengths of the crash barrier had yet to be installed.

Maitland waded through the grass to the front of his car. A single glance told him that he had no hope of driving it to a nearby access road. The front end had been punched into itself like a collapsed face. Three of the four headlamps were broken, and the decorative grille was meshed into the radiator honeycomb. On impact the suspension units had forced the engine back off its mountings, twisting the frame of the car. The sharp smell of anti-freeze and hot rust cut at Maitland's nostrils as he bent down and examined the wheel housing.

A total write-off – damn it, he had liked the car. He walked through the grass to a patch of clear ground between the Jaguar and the embankment. Surprisingly, no one had yet stopped to help him. As the drivers emerged from the darkness below the overpass into the fast right-hand bend lit by the afternoon sunlight they would be too busy to notice the scattered wooden trestles.

Maitland looked at his watch. It was three eighteen, little more than ten minutes since the crash. Walking about through the grass, he felt almost light-headed, like a man who has just witnessed some harrowing event, a motorway pile-up or public execution… He had promised his eight-year-old son that he would be home in time to collect him from school. Maitland visualized David at that moment, waiting patiently outside the Richmond Park gates near the military hospital, unaware that his father was six miles away, stranded beside a crashed car at the foot of a motorway embankment. Ironically, in this warm spring weather the line of crippled war veterans would be sitting in their wheel chairs by the park gates, as if exhibiting to the boy the variety of injuries which his father might have suffered.

Maitland went back to the Jaguar, steering the coarse grass out of the way with his hands. Even this small exertion flushed his face and chest. He looked round for the last time, with the deliberate gaze of a man inspecting an unhappy terrain he is about to leave for ever. Still shaken by the crash, he was already aware of the bruises across his thighs and chest. The impact had hurled him like a broken punch-bag on to the steering wheel – the second collision, as safety engineers modestly termed it. Calming himself, he leaned against the Jaguar's trunk; he wanted to fix in his mind this place of wild grass and abandoned cars where he had very nearly lost his life.

Shielding his eyes from the sunlight, Maitland saw that he had crashed into a small traffic island, some two hundred yards long and triangular in shape, that lay in the waste ground between three converging motorway routes. The apex of the island pointed towards the west and the declining sun, whose warm light lay over the distant television studios at White City. The base was formed by the southbound overpass that swept past seventy feet above the ground. Supported on massive concrete pillars, its six lanes of traffic were sealed from view by the corrugated metal splash-guards installed to protect the vehicles below.

Behind Maitland was the northern wall of the island, the thirty-feet-high embankment of the westbound motorway from which he had crashed. Facing him, and forming the southern boundary, was the steep embankment of the three-lane feeder road which looped in a north-westerly circuit below the overpass and joined the motorway at the apex of the island. Although no more than a hundred yards away, this freshly grassed slope seemed hidden behind the overheated light of the island, by the wild grass, abandoned cars and builder's equipment. Traffic moved along the westbound lanes of the feeder road, but the metal crash barriers screened the island from the drivers. The high masts of three route indicators rose from concrete caissons built into the shoulder of the road.

Maitland turned as an airline coach passed along the motorway. The passengers on the upper deck, bound for Zurich, Stuttgart and Stockholm, sat stiffly in their seats like a party of mannequins. Two of them, a middle-aged man in a white raincoat and a young Sikh wearing a turban on his small head, looked down at Maitland, catching his eyes for a few seconds. Maitland returned their gaze, deciding not to wave at them. What did they think he was doing there? From the upper deck of the bus his Jaguar might well appear to be undamaged, and they would assume that he was a highway official or traffic engineer.

Below the overpass, at the eastern end of the island, a wire-mesh fence sealed off the triangle of waste ground from the area beyond, which had become an unofficial municipal dump. In the shadows below the concrete span were several derelict furniture vans, a stack of stripped-down billboards, mounds of tyres and untreated metal refuse. A quarter of a mile to the east of the overpass, visible through the fence, was a neighbourhood shopping centre. A red double-decker bus circled a small square, passing the striped awnings of multiple stores.

Clearly there was no exit from the island other than the embankments. Maitland removed the ignition keys from the instrument panel and unlocked the Jaguar's trunk. The chances of a wandering tramp or tinker finding the car were slight – the island was sealed off from the world around it by the high embankments on two sides and the wire-mesh fence on its third. The compulsory landscaping had yet to be carried out by the contractors, and the original contents of this shabby tract, its rusting cars and coarse grass, were still untouched.