‘Judith!’ he shouted to the empty house. ‘Damn!’

The pain mounted, an intense prickling that drove silver needles through his skull. Helpless for a moment, he propelled himself into the bedroom and climbed fully dressed into the bed, shielding his eyes from the weak sunlight which crossed the Heath.

After a few minutes the attack subsided slightly, leaving him with a nagging migraine and a sense of utter inertia. For the next hour he stared at the reflection of himself in the dressing-table mirror, lying like a trussed steer across the bed. Through the window he watched a small boy playing under the oaks by the edge of the park, patiently trying to catch the spiralling leaves. Twenty yards away a nondescript little man with a dark complexion sat alone on a bench, staring through the trees.

In some way this scene soothed Elliott, and the headache finally dissipated, as if charmed away by the swaying boughs and the leaping figure of the boy.

‘Strange .’ he murmured to himself, still puzzled by the ferocity of the attack. Judith, however, would be sceptical; she had always accused him of being a hypochondriac. It was a pity she hadn’t been there, instead of lying about on the beach at Worthing, but at least the children had been spared the spectacle of their father yelping with agony.

Reluctant to get out of bed and precipitate another attack — perhaps it was due to some virulent but short-lived virus? Elliott lay back, the scent of his wife’s skin on the pillow reminding him of his own childhood and his mother’s perfumed hair. He had been brought up in India, and remembered being rowed across a river by his father, the great placid back of the Ganges turning crimson in the late afternoon light. The burnt-earth colours of the Calcutta waterfront were still vivid after an interval of thirty years.

Smiling pleasantly over this memory, and at the image of his father rowing with a rhythmic lulling motion, Elliott gazed upward at the ceiling, only distracted by the distant hoot of a car horn.

Then he sat up abruptly, staring sharply at the room around him.

‘Calcutta? What the hell—?’

The memory had been completely false! He had never been to India in his life, or anywhere near the Far East. He had been born in London, and lived there all his life apart from a two-year postgraduate visit to the United States. As for his father, who had been captured by the Germans while fighting with the Eighth Army in North Africa and spent most of the war as a POW, Elliott had seen almost nothing of him until his adolescence.

Yet the memory of being rowed across the Ganges had been extraordinarily strong. Trying to shake off the last residue of the headache, Elliott swung his feet onto the floor. The throbbing had returned slightly, but in a curious way receded as he let the image of the Calcutta waterfront fill his mind. Whatever its source, the landscape was certainly Indian, and he could see the Ganges steps, a clutter of sailing dhows and even a few meagre funeral pyres smoking on the embankment.

But what most surprised him were the emotional associations of this false memory of being rowed by his father, the sense of reassurance that came with each rhythmic motion of the dark figure, whose face was hidden by the shadows of the setting sun.

Wondering where he had collected this powerful visual impression which had somehow translated itself into a memory with unique personal undertones, Elliott left the bedroom and made his way down to the kitchen. It was now half past two, almost too late for lunch, and he stared without interest at the rows of eggs and milk bottles in the refrigerator. After lunch, he decided, he would settle down on the sofa in the lounge and read or watch television.

At the thought of the latter Elliott realized that the false memory of the Ganges was almost certainly a forgotten fragment of a film travelogue, probably one he had seen as a child. The whole sequence of the memory, with its posed shot of the boat cutting through the crimson water and the long traverse of the waterfront, was typical of the style of the travelogues made in the nineteen-forties, and he could almost see the credit titles coming up with a roll of drums.

Reassured by this, and assuming that the headache had somehow jolted loose this visual memory — the slightly blurred wartime cinema screens had often strained his eyes — Elliott began to prepare his lunch. He ignored the food Judith had left for him and hunted among the spices and pickle jars in the pantry, where he found some rice and a packet of curry powder. Judith had never mastered the intricacies of making a real curry, and Elliott’s own occasional attempts had merely elicited amused smiles. Today, however, with ample time on his hands and no interference, he would succeed.

Unhurriedly Elliott began to prepare the dish, and the kitchen soon filled with steam and the savoury odours of curry powder and chutney. Outside, the thin sunlight gave way to darker clouds and the first afternoon rain. The small boy had gone, but the solitary figure under the oaks still sat on the bench, jacket collar turned up around his neck.

Delighted by the simmering brew, Elliott relaxed on his stool, and thought about his medical practice. Normally he would have been obliged to hold an evening surgery, but his locum had arranged to take over for him, much to his relief, as one of the patients had been particularly difficult — a complete neurotic, a hazard faced by every doctor, she had even threatened to report him to the general medical council for misconduct, though the allegations were so grotesque the disciplinary committee would not consider them seriously for a moment.

The curry had been strong, and a sharp pain under the sternum marked the beginning of a bout of indigestion. Cursing his bad luck, Elliott poured a glass of milk, sorry to lose the flavour of the curry.

‘You’re in bad shape, old sport,’ he said to himself with ironic humour. ‘You ought to see a doctor.’

With a sudden snap of his fingers he stood up. He had experienced his second false memory! The whole reverie about his medical practice, the locum and the woman patient were absolute fictions, unrelated to anything in his life. Professionally he was a research chemist, employed in the biochemistry department of one of the London cancer institutes, but his contacts with physicians and surgeons were virtually nil.

And yet the impression of having a medical practice, patients and all the other involvements of a busy doctor was remarkably strong and persistent — indeed, far more than a memory, a coherent area of awareness as valid as the image of the biochemistry laboratory.

With a growing sense of unease, Elliott sipped weakly at the tumbler of milk, wondering why these sourceless images, like fragments from the intelligence of some other individual, were impinging themselves on his mind. He went into the lounge and sat down with his back to the window, examining himself with as much professional detachment as he could muster. Behind him, under the trees in the park, the man on the bench sat silently in the rain, eyed at a safe distance by a wandering mongrel.

After a pause to collect himself, Elliott deliberately began to explore this second false memory. Immediately he noticed that the dyspepsia subsided, as if assuming the persona of the fragmented images relieved their pressure upon his mind. Concentrating, he could see a high window above a broad mahogany desk, a padded leather couch, shelves of books and framed certificates on the walls, unmistakably a doctor’s consulting rooms. Leaving the room, he passed down a broad flight of carpeted stairs into a marble-floored hall. A desk stood in an alcove on the left, and a pretty red-haired receptionist looked up and smiled to him across her typewriter. Then he was outside in the street, obviously in a well-to-do quarter of the city, where Rolls-Royces and Bentleys almost outnumbered the other cars. Two hundred yards away double-decker buses crossed a familiar intersection.