The mingled smells of hot horse and cold river mist filled my nostrils. I could hear only the swish and thud of galloping hooves and the occasional sharp click of horseshoes striking against each other. Behind me, strung out, rode a group of men dressed like myself in white silk breeches and harlequin jerseys, and in front, his body vividly red and green against the pale curtain of fog, one solitary rider steadied his horse to jump the birch fence stretching blackly across his path.

All, in fact, was going as expected. Bill Davidson was about to win his ninety-seventh steeplechase. Admiral, his chestnut horse, was amply proving he was still the best hunter 'chaser in the kingdom, and I, as often before, had been admiring their combined back view for several minutes.

Ahead of me the powerful chestnut hindquarters bunched, tensed, sprang: Admiral cleared the fence with the effortlessness of the really good performer. And he'd gained another two lengths, I saw, as I followed him over. We were down at the far end of Maidenhead racecourse with more than half a mile to go to the winning post. I hadn't a hope of catching him.

The February fog was getting denser. It was now impossible to see much farther than from one fence to the next, and the silent surrounding whiteness seemed to shut us, an isolated string of riders, into a private lonely limbo. Speed was the only reality. Winning post, crowds, stands, and stewards, left behind in the mist, lay again invisibly ahead, but on the long deserted mile and a half circuit it was quite difficult to believe they were really there.

It was an eerie, severed world in which anything might happen. And something did.

We rounded the first part of the bend at the bottom of the racecourse and straightened to jump the next fence. Bill was a good ten lengths in front of me and the other horses, and hadn't exerted himself. He seldom needed to.

The attendant at the next fence strolled across the course from the outside to the inside, patting the top of the birch as he went, and ducked under the rails. Bill glanced back over his shoulder and I saw the flash of his teeth as he smiled with satisfaction to see me so far behind. Then he turned his head towards the fence and measured his distance.

Admiral met the fence perfectly. He rose to it as if flight were not only for the birds.

And he fell.

Aghast, I saw the flurry of chestnut legs threshing the air as the horse pitched over in a somersault. I had a glimpse of Bill's bright-clad figure hurtling head downwards from the highest point of his trajectory, and I heard the crash of Admiral landing upside down after him.

Automatically I swerved over to the right and kicked my horse into the fence. In mid-air, as I crossed it, I looked down at Bill. He lay loosely on the ground with one arm outstretched. His eyes were shut. Admiral had fallen solidly, back downwards, across Bill's unprotected abdomen, and he was rolling backwards and forwards in a frantic effort to stand up again.

I had a brief impression that something lay beneath them. Something incongruous, which ought not to be there. But I was going too fast to see properly.

As my horse pressed on away from the fence, I felt as sick as if I'd been kicked in the stomach myself. There had been a quality about that fall which put it straight into the killing class.

I looked over my shoulder. Admiral succeeded in getting to his feet and cantered off loose, and the attendants stepped forward and bent over Bill, who still lay motionless on the ground. I turned back to attend to the race. I had been left in front and I ought to stay there. At the side of the course a black-suited, white-sashed First-Aid man was running towards and past me.

He had been standing at the fence I was now approaching, and was on his way to help Bill.

I booted my horse into the next three fences, but my heart was no longer in it, and when I emerged as the winner into the full view of the crowded stands, the mixed gasp and groan which greeted me seemed an apt enough welcome. I passed the winning post, patted my mount's neck, and looked at the stands. Most heads were still turned towards the last fence, searching the impenetrable mist for Admiral, the odds-on certainty who had lost his first race for two years.

Even the pleasant middle-aged woman whose horse I was riding met me with the question 'What happened to Admiral?'

'He fell,' I said.

'How lucky,' said Mrs Mervyn, laughing happily.

She took hold of the bridle and led her horse into the winner's unsaddling enclosure. I slid off and undid the girth buckles with fingers clumsy from shock. She patted the horse and chattered on about how delighted she was to have won, and how unexpected it was, and how fortunate that Admiral had tripped up for a change, though a great pity in another way, of course.

I nodded and smiled at her and didn't answer, because what I would have said would have been savage and unkind. Let her enjoy her win, I thought. They come seldom enough. And Bill might, after all, be all right.

I tugged the saddle off the horse and, leaving a beaming Mrs Mervyn receiving congratulations from all around, pressed through the crowd into the weighing room. I sat on the scales, was passed as correct, walked into the changing room, and put my gear down on the bench.

Clem, the racecourse valet who looked after my stuff, came over. He was a small elderly man, very spry and tidy, with a weatherbeaten face and wrists whose tendons stood out like tight strung cords.

He picked up my saddle and ran his hand caressingly over the leather. It was a habit he had grown into, I imagined, from long years of caring for fine-grained skins. He stroked a saddle as another man would a pretty girl's cheek, savouring the suppleness, the bloom.

'Well done, sir,' he said; but he didn't look overjoyed.

I didn't want to be congratulated. I said abruptly, 'Admiral should have won.'

'Did he fall?' asked Clem anxiously.

'Yes,' I said. I couldn't understand it, thinking about it.

'Is Major Davidson all right, sir?' asked Clem. He valeted Bill too and, I knew, looked upon him as a sort of minor god.

'I don't know,' I said. But the hard saddle-tree had hit him plumb in the belly with the weight of a big horse falling at thirty miles an hour behind it. What chance has he got, poor beggar, I thought.

I shrugged my arms into my sheepskin coat and went along to the First-Aid room. Bill's wife, Scilla, was standing outside the door there, pale and shaking and doing her best not to be frightened. Her small neat figure was dressed gaily in scarlet, and a mink hat sat provocatively on top of her cloudy dark curls. They were clothes for success, not sorrow.

'Alan,' she said, with relief, when she saw me. 'The doctor's looking at him and asked me to wait here. What do you think? Is he bad?' She was pleading, and I hadn't much comfort to give her. I put my arm round her shoulders.

She asked me if I had seen Bill fall, and I told her he had dived on to his head and might be slightly concussed.

The door opened, and a tall slim well-groomed man came out. The doctor.

'Are you Mrs Davidson?' he said to Scilla. She nodded.

'I'm afraid your husband will have to go along to the hospital,' he said. 'It wouldn't be sensible to send him home without an X-ray.' He smiled reassuringly, and I felt some of the tension go out of Scilla's body.

'Can I go in and see him?' she said.

The doctor hesitated. 'Yes,' he said finally, 'but he's almost unconscious. He had a bit of a bang on the head. Don't try to wake him.'