However, unless he could tell the exact time at any given moment, he knew he would go mad.

His obsession, which now faced him with a charge of murder, had revealed itself innocently enough.

As a child, like all children, he had noticed the occasional ancient clock tower, bearing the same white circle with its twelve intervals. In the seedier areas of the city the round characteristic dials often hung over cheap jewellery stores, rusting and derelict.

‘Just signs,’ his mother explained. ‘They don’t mean anything, like stars or rings.’

Pointless embellishment, he had thought.

Once, in an old furniture shop, they had seen a clock with hands, upside down in a box full of fire-irons and miscellaneous rubbish.

‘Eleven and twelve,’ he had pointed out. ‘What does it mean?’

His mother had hurried him away, reminding herself never to visit that street again. Time Police were still supposed to be around, watching for any outbreak. ‘Nothing,’ she told him sharply. ‘It’s all finished.’ To herself she added experimentally: Five and twelve. Five to twelve. Yes.

Time unfolded at its usual sluggish, half-confused pace. They lived in a ramshackle house in one of the amorphous suburbs, a zone of endless afternoons. Sometimes he went to school, until he was ten spent most of his time with his mother queueing outside the closed food stores. In the evenings he would play with the neighbourhood gang around the abandoned railway station, punting a home-made flat car along the overgrown tracks, or break into one of the unoccupied houses and set up a temporary command post.

He was in no hurry to grow up; the adult world was unsynchronized and ambitionless. After his mother died he spent long days in the attic, going through her trunks and old clothes, playing with the bric-à-brac of hats and beads, trying to recover something of her personality.

In the bottom compartment of her jewellery case he came across a small flat gold-cased object, equipped with a wrist strap. The dial had no hands but the twelve-numbered face intrigued him and he fastened it to his wrist.

His father choked over his soup when he saw it that evening.

‘Conrad, my God! Where in heaven did you get that?’

In Mamma’s bead box. Can’t I keep it?’

‘No. Conrad, give it to me! Sorry, son.’ Thoughtfully: ‘Let’s see, you’re fourteen. Look, Conrad, I’ll explain it all in a couple of years.’

With the impetus provided by this new taboo there was no need to wait for his father’s revelations. Full knowledge came soon. The older boys knew the whole story, but strangely enough it was disappointingly dull.

‘Is that all?’ he kept saying. ‘I don’t get it. Why worry so much about clocks? We have calendars, don’t we?’

Suspecting more, he scoured the streets, carefully inspecting every derelict clock for a clue to the real secret. Most of the faces had been mutilated, hands and numerals torn off, the circle of minute intervals stripped away, leaving a shadow of fading rust. Distributed apparently at random all over the city, above stores, banks and public buildings, their real purpose was hard to discover. Sure enough, they measured the progress of time through twelve arbitrary intervals, but this seemed barely adequate grounds for outlawing them. After all, a whole variety of timers were in general use: in kitchens, factories, hospitals, wherever a fixed period of time was needed. His father had one by his bed at night. Sealed into the standard small black box, and driven by miniature batteries, it emitted a high penetrating whistle shortly before breakfast the next morning, woke him if he overslept. A clock was no more than a calibrated timer, in many ways less useful, as it provided you with a steady stream of irrelevant information. What if it was half past three, as the old reckoning put it, if you weren’t planning to start or finish anything then?

Making his questions sound as na•ve as possible, he conducted a long, careful poll. Under fifty no one appeared to know anything at all about the historical background, and even the older people were beginning to forget. He also noticed that the less educated they were the more they were willing to talk, indicating that manual and lower-class workers had played no part in the revolution and consequently had no guilt-charged memories to repress. Old Mr Crichton, the plumber who lived in the basement apartment; reminisced without any prompting, but nothing he said threw any light on the problem.

‘Sure, there were thousands of clocks then, millions of them, everybody had one. Watches we called them, strapped to the wrist, you had to screw them up every day.’

‘But what did you do with them, Mr Crichton?’ Conrad pressed.

‘Well, you just — looked at them, and you knew what time it was. One o’clock, or two, or half past seven — that was when I’d go off to work.’

‘But you go off to work now when you’ve had breakfast. And if you’re late the timer rings.’

Crichton shook his head. ‘I can’t explain it to you, lad. You ask your father.’

But Mr Newman was hardly more helpful. The explanation promised for Conrad’s sixteenth birthday never materialized. When his questions persisted Mr Newman tired of side-stepping, shut him up with an abrupt: ‘Just stop thinking about it, do you understand? You’ll get yourself and the rest of us into a lot of trouble.’

Stacey, the young English teacher, had a wry sense of humour, liked to shock the boys by taking up unorthodox positions on marriage or economics. Conrad wrote an essay describing an imaginary society completely preoccupied with elaborate rituals revolving around a minute by minute observance of the passage of time.

Stacey refused to play, however, gave him a non-committal beta plus, after class quietly asked Conrad what had prompted the fantasy. At first Conrad tried to back away, then finally came out with the question that contained the central riddle.

‘Why is it against the law to have a clock?’

Stacey tossed a piece of chalk from one hand to the other.

‘Is it against the law?’

Conrad nodded. ‘There’s an old notice in the police station offering a bounty of one hundred pounds for every clock or wristwatch brought in. I saw it yesterday. The sergeant said it was still in force.’

Stacey raised his eyebrows mockingly. ‘You’ll make a million. Thinking of going into business?’

Conrad ignored this. ‘It’s against the law to have a gun because you might shoot someone. But how can you hurt anybody with a clock?’

‘Isn’t it obvious? You can time him, know exactly how long it takes him to do something.’

‘Well?’

‘Then you can make him do it faster.’

At seventeen, on a sudden impulse, he built his first clock. Already his preoccupation with time was giving him a marked lead over his class-mates. One or two were more intelligent, others more conscientious, but Conrad’s ability to organize his leisure and homework periods allowed him to make the most of his talents. When the others were lounging around the railway yard on their way home Conrad had already completed half his prep, allocating his time according to its various demands.

As soon as he finished he would go up to the attic playroom, now his workshop. Here, in the old wardrobes and trunks, he made his first experimental constructions: calibrated candles, crude sundials, sand-glasses, an elaborate clockwork contraption developing about half a horse power that drove its hands progressively faster and faster in an unintentional parody of Conrad’s obsession.

His first serious clock was water-powered, a slowly leaking tank holding a wooden float that drove the hands as it sank downwards. Simple but accurate, it satisfied Conrad for several months while he carried out his ever-widening search for a real clock mechanism. He soon discovered that although there were innumerable table clocks, gold pocket watches and timepieces of every variety rusting in junk shops and in the back drawers of most homes, none of them contained their mechanisms. These, together with the hands, and sometimes the digits, had always been removed. His own attempts to build an escapement that would regulate the motion of the ordinary clockwork motor met with no success; everything he had heard about clock movements confirmed that they were precision instruments of exact design and construction. To satisfy his secret ambition — a portable timepiece, if possible an actual wristwatch — he would have to find one, somewhere, in working order.