When the Sha Tin race course opened in 1985, you could gaze from the grandstand and wonder what lay over the Shing Mun river. There were a few villages dotted on the far shore, but most people watching their horses limp into fourth place had never been there; the road linking Sha Tin to Sai Kung didn't open to the public until 1988. A decade ago, Ma On Shan and its associated satellite towns did not exist. A few Hakka farmers grew bok choi and the occasional fishing junk (more often, smuggling craft) dropped anchor. Today, the population nears 200,000. The new road allowed people to drive from Sha Tin to Sai Kung and opened up vast areas of pleasant countryside which was formerly unreachable. Land developers swarmed in, as did picnickers and kite-fliers. By the speedometer on my bicycle, it is an energetic 33 kilometres from where I live in Sha Tin to the Duke of York pub in Sai Kung. On weekday afternoons it is a pleasant journey, as long as you stick to the bike tracks and footpaths. Between Ma On Shan and Wong Chuk Wan there is seldom much traffic. You can admire the butterflies and enjoy the quiet. Not long after the road opened, I was pedalling along one Thursday afternoon, minding my own business and thinking pleasant thoughts, when a policeman imperiously waved me to an abrupt halt. 'No,' he said. Being a law-abiding fellow, I stopped. So did all cars going in the same direction. For about five minutes, I waited patiently. Then I asked the policeman what was going on. Accident? Land slide? Road works? 'No talk,' the constable snapped. I took another look at this officious young man. He was wearing the blue winter uniform. But he did not have a gun. And he was wearing black gym shoes. Any policeman turned out like this would have incurred the instant wrath of the commissioner, who at that time was the awesome Li Kwan-ha. 'Hey,' I demanded in Cantonese. 'Are you a policeman?' He gave me an offhand, dismissive wave. I mounted my bike and started off up the road, with this brute yelling at me and galloping along in close pursuit. About 300 metres further on, on a flat disused paddy field, there was assembled the armed cavalry of the Tang dynasty. Horses cantered about and fellows in flowing robes waved swords and spears. An historical drama was being made by a freelance movie company. My policeman, it turned out, was an extra dressed up in a false uniform whose job it was to stop traffic so the film could be shot. I reported this cheeky closure of the Queen's highway (as it was then) to Sai Kung police station, where a weary inspector complained that such events happened all the time. There is no ban, of course, on making movies in Hong Kong. It is against the law, however, to wear police uniforms or carry fake weapons without permission. The police usually bend over backwards to accommodate film-makers. It is a sensible attitude and helps support an important industry, as well as indirectly creating a good image for our community. Movie companies are encouraged to tell the Police Public Relations Bureau when they are making a film - in town as well as country - so local coppers can help them. If a cops and robbers movie is being made, the head of the bureau, the extremely obliging Harry Blud, considers applications to wear imitation police uniforms, which are invariably approved. Film companies can also hire uniformed policemen as extras, as well as police cars and boats, as long as this does not interfere with their main responsibilities of protecting the public and its property. The money goes into general police funds. In reality, renegade movie-makers break the laws virtually every week. At night in remote areas, the roar of racing engines and the squeal of tortured tyres indicate a high-speed chase is being staged for the cameras. These people are never caught. Even if they were, a $1,000 fine, which is the maximum for misuse of a police uniform, would not deter them. There is a special six-page guideline put out by the police to aid legitimate film-makers, a document which it seems to me is totally ignored by fringe movie-makers operating on tight freelance budgets. They prefer to endanger people by staging car chases and hijack the public highways to obtaining official permission. So next time you are stopped by a policeman on a lonely road, get a good look at his uniform. Take care, however, before giving him a backwards V sign and speeding off: chances are he may be genuine.