The traffic multiplied, concrete lanes moving laterally across the landscape. As Catherine and I drove from the coroner's inquest the flyovers overlaid one another like copulating giants, immense legs straddling each other's backs. A verdict of accidental death had been returned, without any show of interest or ceremony; no charges of manslaughter or negligent driving were brought against me by the police. After the inquest I let Catherine drive me to the airport. For half an hour I sat by the window in her office, looking down at the hundreds of cars in the parking lot. Their roofs formed a lake of metal. Catherine's secretary stood behind her shoulder, waiting for me to leave. As she handed Catherine's glasses to her I saw that she was wearing a white lipstick, presumably an ironic concession to this day of death.

Catherine walked me to the lobby. 'Jam68? you must go to the office – believe me, love, I'm trying to be helpful.' She touched my right shoulder with a curious hand, as if searching for some new wound which had flowered there. During the inquest she had held my arm in a peculiar grip, frightened that I might be swept sideways out of the window. Unwilling to haggle with the surly and baronial taxi-drivers only interested in taking London fares, I walked through the car-park opposite the air-freight building. Overhead, across the metallized air, a jet-liner screamed. When the aircraft had passed I raised my head and saw Dr Helen Remington moving among the cars a hundred yards to my right.

At the inquest I had been unable to take my eyes away from the scar on her face. I watched her walk calmly through the lines of cars towards the entrance of the immigration department. Her strong jaw was held at a jaunty angle, her face turned away from me as if she were ostentatiously blotting out all traces of my existence. At the same time I had the strong impression that she was completely lost.

A week after the inquest she was waiting at the taxi rank of the Oceanic Terminal as I drove away from Catherine's office. I called to her and stopped behind an airline bus, beckoning her into the passenger seat. Swinging her handbag from a strong wrist, she came across to my car, recognizing me with a grimace.

As we headed towards Western Avenue she surveyed the traffic with frank interest. She had brushed her hair back from her face, openly wearing the fading scar-line.

'Where can I take you?'

'Can we drive a little?' she asked. 'There's all this traffic – I like to look at it.'

Was she trying to taunt me? I guessed that in her matter-of-fact way she was already assessing the possibilities I had revealed to her. From the concrete aprons of the parking lots and the roofs of the multi-storey car-parks she was now inspecting with a clear and unsentimental eye the technology which had brought about the death of her husband.

She began to chatter with contrived animation. 'Yesterday I hired a taxi-driver to drive me around for an hour. "Anywhere," I said. We sat in a massive traffic jam near the underpass. I don't think we moved more than fifty yards. He wasn't in the least put out.'

We drove along Western Avenue, the service buildings and perimeter fence of the airport on our left. I kept the car in the slow lane as the high deck of the flyover receded in the rear-view mirror. Helen talked about the second life she was already planning for herself.

'The Road Research Laboratory need a medical officer – the salary is larger, something I've got to think about now. There's a certain moral virtue in being materialistic.'

The Road Research Laboratory…' I repeated. The newsreels of simulated car-crashes were often shown in television documentaries; these mutilated machines were haunted by a strange pathos. 'Isn't that rather too close…?'

That's the point. Besides, I know I can give something now that I wasn't remotely aware of before. It's not a matter of duty so much as of commitment.'

Fifteen minutes later, as we moved back towards the flyover, she came and sat beside me, watching my hands on the controls as we once again entered the collision course.

The same calm but curious gaze, as if she were still undecided how to make use of me, was fixed on my face shortly afterwards as I stopped the car on a deserted service road among the reservoirs to the west of the airport. When I put my arm around her shoulders she smiled briefly to herself, a nervous rictus of the upper lip which exposed her gold-tipped right incisor. I touched her mouth with my own, denting the waxy carapace of pastel lipcoat, watching her hand reach out to the chromium pillar of the quarter window. I pressed my lips against the bared and unmarked dentine of her upper teeth, fascinated by the movement of her fingers across the smooth chrome of the window pillar. Its surface was marked along its forward edge by a smear of blue paint left by some disaffected production-line worker. The nail of her forefinger scratched at this fretline, which rose diagonally from the window-sill at the same angle as the concrete ledge of the irrigation ditch ten feet from the car. In my eyes this parallax fused with the image of an abandoned car lying in the rust-stained grass on the lower slopes of the reservoir embankment. The brief avalanche of dissolving talc that fell across her eyes as I moved my lips across their lids contained all the melancholy of this derelict vehicle, its leaking engine oil and radiator coolant.

Six hundred yards behind us the traffic waited on the raised deck of the motorway, the afternoon sunlight crossing the windows of the airline buses and cars. My hand moved around the outer curvature of Helen's thighs, feeling the open zip of her dress. As these razor-like links cut my knuckles I felt her teeth across my ear. The sharpness of these pains reminded me of the bite of the windshield glass during my crash. She opened her legs and I began to stroke the nylon mesh that covered her pubis, a glamorous veil for the loins of this serious-minded woman doctor. Looking into her face, with its urgent mouth gasping as if trying to devour itself, I moved her hand around her breasts. She was now talking to herself, rambling away like some demented accident casualty. She lifted her right breast from her brassiere, pressing my fingers against the hot nipple. I kissed each breast in turn, running my teeth across the erect nipples.

Seizing me with her body in this arbour of glass, metal and vinyl, Helen moved her hand inside my shirt, feeling for my nipples. I took her fingers and placed them around my penis. Through the rear-view mirror I saw a water-board maintenance truck approaching. It moved past in a roar of dust and diesel exhaust that drummed against the doors of my car. This surge of excitement drew the first semen to my penis. Ten minutes later, when the truck returned, the vibrating windows brought on my orgasm. Helen knelt across me, elbows pressed into the seat on either side of my head. I lay back, feeling the hot, scented vinyl. My hands pushed her skirt around her waist so that I could see the curve of her hips. I moved her slowly against me, pressing the shaft of my penis against her clitoris. Elements of her body, her square kneecaps below my elbows, her right breast jacked out of its brassiere cup, the small ulcer that marked the lower arc of her nipple, were framed within the cabin of the car. As I pressed the head of my penis against the neck of her uterus, in which I could feel a dead machine, her cap, I looked at the cabin around me. This small space was crowded with angular control surfaces and rounded sections of human bodies interacting in unfamiliar junctions, like the first act of homosexual intercourse inside an Apollo capsule. The volumes of Helen's thighs pressing against my hips, her left fist buried in my shoulder, her mouth grasping at my own, the shape and moisture of her anus as I stroked it with my ring finger, were each overlaid by the inventories of a benevolent technology – the moulded binnacle of the instrument dials, the jutting carapace of the steering column shroud, the extravagant pistol grip of the handbrake. I felt the warm vinyl of the seat beside me, and then stroked the damp aisle of Helen's perineum. Her hand pressed against my right testicle. The plastic laminates around me, the colour of washed anthracite, were the same tones as her pubic hairs parted at the vestibule of her vulva. The passenger compartment enclosed us like a machine generating from our sexual act an homun-culus of blood, semen and engine coolant. My finger moved into Helen's rectum, feeling the shaft of my penis within her vagina. These slender membranes, like the mucous septum of her nose which I touched with my tongue, were reflected in the glass dials of the instrument panel, the unbroken curve of the windshield.

Her mouth bit my left shoulder, blood marking my shirt like the imprint of a mouth. Without thinking, I struck the side of her head with the palm of my hand.

'I'm sorry!' she gasped into my face. 'Please, don't move!' She steered my penis back into her vagina. Holding her buttocks with both hands, I moved rapidly towards my orgasm. Above me, Helen Remington's serious faced gazed down at me as if she were resuscitating a patient. The sheen of moisture on the skin around her mouth was like the bloom on a morning windshield. She pumped her buttocks rapidly, forcing her pubic bone against mine, then leaned back against the dashboard as a Land-Rover thudded past along the track, sending a cloud of dust against the windows.

She lifted herself off my penis when it had gone, letting the semen fall on to my crotch. She sat herself behind the steering wheel, holding the wet glans in her hand. She looked around the compartment of the car, as if speculating on any other uses to which she could put our sexual act. Lit by the afternoon sun, the fading scar on her face marked off these concealed motives like the secret frontier of an annexed territory. Thinking that I might reassure her in some way, I took her left breast from the brassiere and began to stroke it. Stirred happily by its familiar geometry, I gazed at the jewelled grotto of the instrument panel, at the jutting shroud of the steering assembly and the chromium heads of the control switches.

A police car appeared on the service road behind us, its white hull rolling heavily through the dips and ruts. Helen sat up and put away her breast with a deft band. She dressed quickly, and began to remake her face in the mirror of her compact. As abruptly as we had begun, she was now distanced from her own eager sexuality.

However, Helen Remington clearly felt no concern herself at these out-of-character actions, these sexual acts in the cramped compartment of my motor-car parked in various deserted service roads, culs-de-sac and midnight parkways. When I collected her during the following weeks from the house she had rented in Northolt, or waited for her in the reception lounge outside the airport immigration offices, it seemed incredible to me that I had any kind of sexual involvement with this sensitive woman doctor in her white coat, listening indulgently to the self-defeating arguments of some tubercular Pakistani.