"I don't know who killed Moira," he said finally. "Alicia says you did. She told the police it HAD to be you."

"I couldn't have."

"She says the police could break your alibi if they really tried."

I knew that they HAD really tried: they'd checked every separate five minutes of my day, and their manner and their suspicions had been disturbing. "And what do YOU think?" I asked curiously.

His eyelids flickered. "Alicia says…"

I said abruptly, "Your mother says too damned much. Can't you think for yourself?"

He was offended, as he would be. He hooked his arms through those of Debs and Serena and made an announcement. "We three are going to have a drink and a sandwich. If you fall off and kill yourself, no one will miss you."

I smiled at him, though his tone had held no joke.

"And don't be so bloody forgiving," he said.

He whirled the girls away from me and marched them off. I wondered how he'd got the day off from work, though I supposed most people could if they tried. He was a statistician, studying to be an actuary in his insurance company. What were the probabilities, I wondered, of a thirty-two-year-old statistician whose wife had purple fingernails being present when his brother broke his neck at Sandown Park?

Donald and Helen said that they too would run a sandwich to earth (Donald's words) and Helen added earnestly that SHE would care that I finished the race safely, whatever Ferdinand said.

"Thanks," I said, hoping I could believe he rand went back into the changing-room for an interval of thought.

Lucy and Edwin might leave before the end of the afternoon, and so might Donald and Helen, but Ferdinand wouldn't. He liked going racing. He'd said on one mellow occasion that he'd have been quite happy being a bookmaker; he was lightning fast at working out relative odds.

The problem of how to extract Malcolm unseen from the racecourse didn't end, either, with those members of the family I'd talked to. If they were all so certain I knew where Malcolm was, one of the others, more cunning, could be hiding behind trees, waiting to follow me when I left. There were hundreds of trees in Sandown Park.

The first race came and went, and in due course I went out to partner Young Higgins in the second.

Jo as usual had red cheeks from pleasure and hope. George was being gruffly businesslike, also as usual, telling me to be especially careful at the difficult first fence and to go easy up the hill past the stands the first time.

I put Malcolm out of my mind, and also murder and it wasn't difficult. The sky was a clear distant blue, the air crisp with the coming of autumn. The leaves on all those trees were yellowing, and the track lay waiting, green and springy, with the wide fences beckoning to be flown. Simple things; and out there one came starkly face to face with oneself, which I mostly found more exhilarating than frightening. So far, anyway.

Jo said, "Only eight runners, just a perfect number," and George said, as he always did, "Don't lie too far back coming round the last long bend."

I said I would try not to.

Jo's eyes were sparkling like a child's in her sixty-year-old face, and I marvelled that she had never in all that time lost the thrill of expectation in moments like these. There might be villains at every level in horse racing, but there were also people like Jo and George whose goodness and goodwill shone out like searchlights, who made the sport overall good fun and wholesome. Life and death might be serious in the real world, but life and death on a fast steeple chaser on a Friday afternoon in the autumn sunshine was a lighthearted toss-up, an act of health on a sick planet.

I fastened the strap of my helmet, was thrown up on Young Higgins and rode him out onto the track. Perhaps if I'd been a professional and ridden up to ten times as often I would have lost the swelling joy that that moment always gave me: one couldn't grin like a maniac, even to oneself, at a procession of bread-and-butter rides on cold days, sharp tracks, bad horses.

Young Higgins was living up to his name, bouncing on his toes and tossing his head in high spirits. We lined up with the seven others, all of whose riders I happened to know from many past similar occasions. Amateurs came in all guises: there was a mother, an aunt and a grandfather riding that afternoon, besides a journalist, an earl's son, a lieutenant-colonel, a show-jumper and myself. From the stands, only a keen eye could have told one from the other without the guidance of our colours, and that was what amateur racing was all about: the equality, the levelling anonymity of the starting gate.

The tapes went up and we set off with three miles to go, almost two whole circuits, twenty-two jumps and an uphill run to the winning post.

The aunt's horse, too strong for her, took hold of the proceedings and opened up an emphatic lead, which no one else bothered to cut down. The aunt's horse rushed into the difficult downhill first fence and blundered over it, which taught him a lesson and let his rider recover control, and for about a mile after that there were no dramatic excitements. The first race I'd ever ridden in had seemed to pass in a whirling heaving flurry leaving me breathless and exhausted, but time had stretched out with experience until one could watch and think and even talk.

"Give me room, blast you," shouted the lieutenant-colonel on one side of me.

"Nice day," said the earl's son chattily on the other always a clown who enlivened his surroundings.

"Shift your arse!" yelled the mother to her horse, giving him a crack round that part of his anatomy. She was a good rider, hated slow horses, hated not to win, weighed a muscular ten stone and was scornful of the show-jumper, whom she had accused often of incompetence.

The show-jumper, it was true, liked to set his horse right carefully before jumps, as in the show-ring, and hadn't managed to speed up in the several steeplechase races he'd ridden so far. He wasn't in consequence someone to follow into a fence and I avoided him whenever possible.

The journalist was the best jockey in the race, a professional in all but status, and the grandfather was the worst but full of splendid reckless courage. More or less in a bunch, the whole lot of us came round the bottom bend and tackled the last three jumps of the first circuit. The aunt was still in front, then came the lieutenant-colonel, myself and the earl's son in a row, then the mother just behind, with the show-jumper and the grandfather beside her. I couldn't see the journalist: somewhere in the rear, no doubt, biding his wily time.

The lieutenant-colonel's mount made a proper hash of the last of the three fences, jogging both of his rider's feet out of the irons and tipping the military backside into the air somewhere in the region of the horse's mane. Landing alongside and gathering my reins, I saw that the lieutenant-colonel's balance was hopelessly progressing down the horse's galloping shoulder as he fought without success to pull himself back into the saddle.

I put out an arm, grasped his jersey and yanked him upwards and backwards, shifting his disastrous centre of gravity into a more manageable place and leaving him slowing and bumping in my wake as he sat down solidly in the saddle, trying to put his feet back into his flying stirrups, which was never very easy at thirty miles an hour.

He had breathing space to collect things going up the hill, though, as we all did, and we swept round the top bend and down to the difficult fence again with not much change in order from the first time.

Someone had once long ago pulled me back into the saddle in that same way: it was fairly common in jump racing. Someone had also once tipped me straight into the air with an upward wrench of my heel, but that was another story. The lieutenant-colonel was saying "Thanks" and also "Move over, you're crowding me," more or less in the same breath. After crossing the water jump for the second time over on the far side of the track, the show-jumper made a spurt to the front and then slowed almost to a standstill on landing over the next fence, having jumped especially pedantically, and the aunt crashed into the back of him with some singularly un-aunt-like language.