He picked up his car radio and spoke into it to the effect that Mr Ian Pembroke had come by. A request came back, which he relayed to me: would Mr Pembroke please drop in at the police station when he left? Mr Pembroke would.

The policeman and I walked round to the back of the house. Mr Smith had gone, also his helpers. The last of the rubble was away from the house and overflowing a skip. A flat black plastic sheet, the sort used for roofing hayricks, lay where a week ago the walls of my bedroom had come tumbling down. The interior doors had been scaled with plywood, like the windows, to deter looters, and the broken end of the staircase had been barred off. A house with its centre torn out; a thirty-foot yawn between surviving flanks.

"It looks terrible," I said, and the policeman agreed.

Arthur Bellbrook was cleaning his spades, getting ready to leave. I gave him a cheque for his wages for that week and the next, and added a chunk for the care of the dogs. He gave me dignified thanks. He hoped Mr Pembroke was all right, poor man, and I said I thought so.

"I had my picture in the paper," he said. "Did you see it?"

I said I was sorry I hadn't.

"Oh, well. I did." He shrugged disappointedly and set off homewards, and I walked down to where he'd earlier been digging potatoes, and then further, to check that the nettles were still un trampled on the far side of the wall.

The green sea looked dusty and ageing but upright. They too, I supposed, would die with the frost.

The policeman was watching me in curiously I stopped and stared at the house from a distance, giving the impression that that's why I had gone as far as I had, and then walked back and took my leave. The house from a distance looked just as bad, if not worse.

Superintendent Yale shook my hand. Things were almost friendly at the police station but they were no nearer discovering who had planted the bomb. Enquiries were proceeding, the superintendent said, and perhaps I could help.

"Fire away," I said.

"We interviewed the former gardener, Fred Perkins," Yale said. "We asked him about the tree stump and what he used to blow it up. Besides cordite, that is. What sort of a fuse."

I was interested. "What did he say? Does he remember?"

"He said he'd got the black powder and some detonators and some fuse cord from a quarry man friend of his. The black powder was in the box which we saw, the detonators were in a separate tin with the cord and the instructions."

"The instructions," I repeated incredulously.

"Yes." He sighed. "Fred Perkins says he followed the instructions because he'd never blown anything up before. He said he used a bit of extra black powder just to make sure."

"it was quite an explosion."

"Yes. We asked him what he'd done with the other detonators. He says Mr Pembroke took them away from him that morning, when he came running out of the house. We need to ask Mr Pembroke what he did with them, so… er… where is he?"

"I really don't know," I said slowly, "and that's the truth. I can probably find him, but it'll take a day or two." I thought for a moment, then said, "Surely' he would have thrown away those detonators years ago."

"If he had any sense he wouldn't have thrown them anywhere," Yale said. "Mr Smith says you handle detonators with extreme caution if you don't want to lose a finger or an eye. They can explode if you knock or drop them or make them too warm. Mr Pembroke's correct course would have been to turn them over to the Police."

"Maybe he did," I said.

"We'd like to find out."

"But would detonators still detonate after twenty years?" I asked.

"Mr Smith thinks it possible, perhaps likely. He wouldn't take any liberties, he said."

"What does a detonator look like?" I asked.

He hesitated, but said, "Mr Smith said we might be looking for a small aluminium tube about the thickness of a pencil or slightly less, about six centimetres long. He says that's what the army used. He used to be in the Royal Engineers. He says the tube contains fulminate of mercury, and the word 'fulminate' means to flash like lightning."

"He should know."

"Fred Perkins can't clearly remember what his detonators looked like. He remembers he had to fasten the cord into the end of the tube with pliers. Crimp it in. Mr Smith says civilians who touch explosives should be certified."

I reflected. "Did Mr Smith find out exactly what the Quantum bomb was made of?"

"Yes. ANFO, as he thought. He said the whole thing was amateur in the extreme."

"Amateurs," I said dryly, "run faster than anyone else."

As an amateur, I went to Kempton Park the next day and on Young Higgins beat the hell out of a lot of professionals.

I didn't know what possessed me. It seemed that I rode on a different plane. I knew it was the horse who had to be fast enough; the jockey, however determined, couldn't do it on his own. Young Higgins seemed inspired and against more formidable opponents than at Sandown produced a totally different race.

There were no aunts riding this time, no lieutenant-colonels falling off. No earl's son to chat to. No journalist to make it look easy. For some reason, George and Jo had entered Young Higgins in a high-class open three-mile steeplechase, and I was the only amateur in sight.

I'd ridden against an all-professional field of top jockeys a few times before, and it was usually a humbling experience. I had the basic skills and a good deal of touch. I could get horses settled and balanced. I liked speed, I liked the stretch of one's spirit: but there was always a point against top professionals at which that wasn't enough.

George and Jo were un fussed Young Higgins was fitter than at Sandown, they thought, and at Kempton there was no hill to tire him. They were bright-eyed and enthusiastic, but not especially hopeful.

"We didn't want to change you for a professional," they said in explanation. "It wouldn't have been fair."

Maybe not fair, but prudent, I thought. The top pros raced with sharper eyes, better tactics, more strength, quicker reactions. Theirs was an intenser determination, a fiercer concentration. Humour was for before and after, not during. Race-riding was their business, besides their pleasure, and some of them thought of amateur opponents as frivolous unfit nuisances who caused accidents and endangered lives.

Perhaps because of an arrogant desire to prove them wrong, perhaps because of the insights and realities I'd faced in a traumatic week, perhaps because of Young Higgins himself: I rode anyway with a new sharp revelationary perception of what was needed for winning, and the horse and I came home in front by four lengths to a fairly stunned silence from the people on the stands who'd backed everything else on the card but us.

George and Jo were vindicated and ecstatic. Young Higgins tossed his head at the modest plaudits. A newspaperman labelled the result as a fluke.

I'd cracked it, I thought. I'd graduated. That had been real professional riding. Satisfactory. But I was already thirty-three. I'd discovered far too late the difference between enjoyment and fire. I'd needed to know it at nineteen or twenty. I'd idled it away.

"This is no time,"Jo said laughing, "to look sad."