Even now, three hours later, all is calm. The leafy avenue is as unruffled as ever. The mail has arrived, and sits unopened on the hail stand. From the dining-room window I watch the British Telecom engineer return to his van after repairing the Johnsons’ telephone, an instrument reduced to a nervous wreck at least twice a month by their teenage daughters. Mrs Johnson, dressed in her turquoise track-suit, closes the gate and glances at my car. A faint vapour rises from the exhaust. The engine is still idling, all these hours after I began to demist the windscreen before finishing my breakfast.

This small slip may give the game away. Watching the car impatiently, I am tempted to step from the house and switch off the ignition, but I manage to control myself. Whatever happens, I must hold to my decision and all the consequences that flow from it. Fortunately, an Air India 747 ambles across the sky, searching none too strenuously for London Airport. Mrs Johnson, who shares something of its heavy-bodied elegance, gazes up at the droning turbo-fans. She is dreaming of Martinique or Mauritius, while I am dreaming of nothing.

My decision to dream that dream may have been made this morning, but I assume that its secret logic had begun to run through my life many months ago. Some unknown source of strength sustained me through the unhappy period of my car accident, convalescence and divorce, and the unending problems that faced me at the merchant bank on my return. Standing by the front door after finishing my coffee, I watched the mist clear from the Volvo’s windscreen. The briefcase in my hand reminded me of the day-long meetings of the finance committee at which I would have to argue once again for the budget of my beleaguered research department.

Then, as I set the burglar alarm, I realised that I could change the course of my life by a single action. To shut out the world, and solve all my difficulties at a stroke, I had the simplest of weapons — my own front door. I needed only to close it, and decide never to leave my house again.

Of course, this decision involved more than becoming a mere stay-at-home. I remember walking into the kitchen, surprised by this sudden show of strength, and trying to work out the implications of what I had done. Still wearing my business suit and tie, I sat at the kitchen table, and tapped out my declaration of independence on the polished formica.

By closing the front door I intended to secede not only from the society around me. I was rejecting my friends and colleagues, my accountant, doctor and solicitor, and above all my ex-wife. I was breaking off all practical connections with the outside world. I would never again step through the front door. I would accept the air and the light, and the electric power and water that continued to flow through the meters. But otherwise I would depend on the outside world for nothing. I would eat only whatever food I could find within the house. After that I would rely on time and space to sustain me.

The Volvo’s engine is still running. It is 3 p.m., seven hours after I first switched on the ignition, but I can’t remember when I last filled the tank. It’s remarkable how few passers-by have noticed the puttering exhaust only the retired headmaster who patrols the avenue morning and afternoon actually stopped to stare at it. I watched him mutter to himself and shake his walking-stick before shuffling away.

The murmur of the engine unsettles me, like the persistent ringing of the telephone. I can guess who is calling: Brenda, my secretary; the head of marketing, Dr Barnes; the personnel manager, Mr Austen (I have already been on sick-leave for three weeks); the dental receptionist (a tender root canal reminds me that I had an appointment yesterday); my wife’s solicitor, insisting that the first of the separation payments is due in six months’ time.

Finally I pick up the telephone cable and pull the jack on this persistent din. Calming myself, I accept that I will admit to the house anyone with a legitimate right to be there — the TV rental man, the gas and electricity meter-readers, even the local police. I cannot expect to be left completely on my own. At the same time, it will be months before my action arouses any real suspicions, and I am confident that by then I will long since have moved into a different realm.

I feel tremendously buoyant, almost lightheaded. Nothing matters any more. Think only of essentials: the physics of the gyroscope, the flux of photons, the architecture of very large structures.

Five p. m. Time to take stock and work out the exact resources of this house in which I have lived for seven years.

First, I carry my unopened mail into the dining room, open a box of matches and start a small, satisfying fire in the grate. To the flames I add the contents of my briefcase, all the bank-notes in my wallet, credit cards, driving licence and cheque-book.

I inspect the kitchen and pantry shelves. Before leaving, Margaret had stocked the freezer and refrigerator with a fortnight’s supply of eggs, ham and other bachelor staples — a pointed gesture, bearing in mind that she was about to sail off into the blue with her lover (a tedious sales manager). These basic rations fulfil the same role as the keg of fresh water and sack of flour left at the feet of a marooned sailor, a reminder of the world rejecting him.

I weigh the few cartons of pasta in my hand, the jars of lentils and rice, the tomatoes and courgettes, the rope of garlic. Along with the tinned anchovies and several sachets of smoked salmon in the freezer, there are enough calories and protein to keep me going for at least ten days, three times that period if I ration myself. After that I will have to boil the cardboard boxes into a nutritious broth and rely on the charity of the wind.

At 6.15 the car’s engine falters and stops.

In every way I am marooned, but a reductive Crusoe paring away exactly those elements of bourgeois life which the original Robinson so dutifully reconstituted. Crusoe wished to bring the Croydons of his own day to life again on his island. I want to expel them, and find in their place a far richer realm formed from the elements of light, time and space.

The first week has ended peacefully. All is well, and I have stabilised my regime most pleasantly. To my surprise, it has been remarkably easy to reject the world. Few people have bothered me. The postman has delivered several parcels, which I carry straight to the dining-room fireplace. On the third day my secretary, Brenda, called at the front door. I smiled winningly, reassured her that I was merely taking an extended sabbatical. She looked at me in her sweet but shrewd way — she had been strongly supportive during both my divorce and the crisis at the office — and then left with a promise to keep in touch. A succession of letters has arrived from Dr Barnes, but I warm my hands over them at the fireplace. The dining-room grate has become an efficient incinerator in which I have erased my entire past passport; birth, degree and share certificates; uncashed traveller’s cheques and 2000 French Francs left from our last unhappy holiday in Nice; letters from my broker and orthopaedic surgeon. Documents of a dead past, they come to life briefly in the flame, and then write themselves into the dust.

Eliminating this detritus has kept me busy. I have pulled down the heavy curtains that hung beside the windows. Light has flooded into the rooms, turning every wall and ceiling into a vivid tabula rasa. Margaret had taken with her most of the ornaments and knickknacks, and the rest I have heaved into a cupboard. Suffused with light, the house can breathe. Upstairs the windows are open to the sky. The rooms seem larger and less confined, as if they too have found freedom. I sleep well, and when I wake in the morning I almost feel myself on some Swiss mountain-top, with half the sky below me.