IT WAS early evening in the concrete jungle of Tuen Mun's Butterfly Estate, and the residents were angry. About 200 had gathered in an impromptu display of fury and frustration. Hours before, burglars had broken into a 16th-floor flat and set it on fire. The fire spread to neighbouring homes and within minutes, six families were homeless. In an urban environment where wanton violence was becoming the norm - there had been 50 copycat arson attacks in neighbouring estates in the past month - it was the final straw. The residents wanted action from the authorities, and quickly. Amid yelling and crying, it took police, district board members and Housing Department officers several hours to calm them down and disperse the crowd. Meanwhile, down the road at the district police station, it was a normal busy Wednesday night. A Mr Chan, with two sons in tow, was at the counter pleading with the duty officer for help. His neighbour had something against his family, and was abusive and threatening every time they met on the staircase. What could he do to protect himself? Minutes later a group of three teenagers walked in. One of them approached the officer, took out his ID card and signed in a large directory. His two friends sat on a bench, casually discussing what they could do to amuse themselves that evening. The youths were on bail, the officer explained, pointing to a long list of names of people who had already reported to the station that day. This is the everyday face of Tuen Mun new town, a planner's dream from the 1960s that for many of its 480,000 inhabitants has turned sour. Last week's murder by a suspected serial rapist at the Yau Oi Estate has brought the town's decaying image into focus. The crime rate in Tuen Mun is not the highest in the territory - Tsuen Wan and Sha Tin come out worse. But for many Tuen Mun residents, their lives are blighted every day by silent fears that might never figure on a police report sheet; fears of triads, of robbers, of loansharks, of young hooligans high on drugs, of drunken neighbours - all exacerbated by the urban stress of living in cramped conditions in sprawling, grey estates. Mr Chan Shun-kin, 41, moved from Shamshuipo to Yau Oi Estate 12 years ago. When his family arrived, it was a pleasant, friendly place. Things have changed drastically. His wife said: ''Two days back we heard some noises from a nearby block at night and we learned later that police were investigating a case of arson. We're sick of these things happening.'' She said her 12-year-old daughter, Wing-sum, was being approached outside school by triads. In a town which is the power base of the Sun Yee On, it is a problem which gets worse every day. With gangs in the streets, she will not let her daughter go out at night. Wing-sum added: ''I have to go home with other classmates after school or leave the school by the back gate. ''They [gangs] usually hang around outside school, smoking and chatting. I don't know what they are up to.'' Mr Chan said about half of his neighbours had moved from the estate, partly to avoid being victimised. Even in newer estates, such as Leung King Estate, it is no urban paradise. Housewives, left alone by husbands working all hours, become addicted to mahjong, and play till late at night, running up debts. They are preyed upon by loansharks, and often turn to illegal hawking to get cash. Loansharks looking for clients place ''advertisements'' inside lifts, public toilets and corridors. The Wan family, which lives on the Tai Hing Estate, regrets the move from Tsuen Wan six years ago. Trainee chef, 16-year-old Wan Kin-keung said his parents argued far more after the move and that his mother had become obsessed with mahjong. He spoke of hearing yelling, whistles, and loud exchanges of foul language by teenage gangs until long after dark. What concerns police, politicians and social workers is the disproportionate rise in juvenile crime. The consensus is that family problems in the new town environment are bringing about a crisis in family life. Mr Raymond Au, deputy chief executive of a voluntary social service agency, Yan Oi Tong, said poor job opportunities in the area prompted many parents to work outside. Children were left unattended, and could fall in with bad elements in amusement arcades or public playgrounds. He said the problem was more serious in older estates, where teenagers knew each other since childhood and could easily form gangs. One of the most shocking court cases of last year was that of 13-year-old Ip Kin-kei, battered to death by his schoolmates at a Tuen Mun estate, apparently over his refusal to get involved with triads. Meeting places for the youngsters are often 7-Elevens and other late-night shops. Miss Cannise Lau, sales supervisor of a convenience store on one estate, said shoplifting took place almost every night. She said gangs were particularly active after midnight at weekends. Many of their members appeared to be on drugs. Assistant District Commander of Crime, Superintendent Ray Pierce, stressed that overall crime in Tuen Mun dropped nine per cent last year, with youth crime accounting for about one third. Superintendent Pierce said he believed the problem stemmed from working parents never having time to see their children. He also blamed the glorification of triad heroes on television and in films. To stop triads from recruiting members from among schoolchildren, the Tuen Mun police set up the Youth Crime Team last December under the District Triad Squad commander. The team speaks to head teachers, interviews children and gives talks in schools. The Yau Oi Estate murder has raised questions as to whether police are adopting a high enough profile. It is not uncommon to hear complaints from housing estate residents that officers are hardly seen until there is an incident. Superintendent Pierce said: ''We always want more men. But we have to be realistic, as recruiting more police officers costs money and we have financial constraints.'' The number of police operations against the Sun Yee On bears witness to the force's efforts to break the circle of lawlessness. But with every member arrested or displaced, more seem to be recruited. When an urban experiment goes wrong, crime is just one of its ugliest faces. Pollution, lack of adequate transport, overstretched education facilities also trouble residents' daily lives. If Tuen Mun was conceived as the ultimate in town living, what went wrong? ALTHOUGH town planners said the first draft of the new town dated as early as the 1960s, it was not until the late 1970s that nine public housing estates were completed, plus factories to provide work. The dream was to relieve population growth in urban Kowloon by providing a high-quality living environment, job opportunities, an integrated modern transport system, recreational activities and basic facilities. The Government town planner for the New Territories, Mr Leung Chun-wai, admitted several early projections had been proved wrong. For example, officials underestimated the number of young couples who would arrive, causing kindergartens and primary schools to be overloaded. Mr Leung said: ''It's unfair to expect development of any new towns to be perfect. There are bound to be growing pains at the initial stage and the Government needs to consider resource allocation from a more macro perspective instead of focusing on one particular new town.'' One of the chief architects of the dream was Sir David Akers-Jones, the district officer and deputy district commissioner of New Territories in the 1960s. Between 1973 and 1985 he was the Secretary for NT Administration. On a trip round the sprawling estates of the town he helped create, Sir David said the place did not deserve its bad image. ''There are lots of good things and successes in Tuen Mun. For example, there are 450,000 people who live here and they can find jobs in a nearby factory area,'' he said. ''But the fact is, we've got to get rid of the unsatisfactory buildings [the old town centre] . . . we need an urban renewal desperately in the old town centre. ''If that is done and we have solved the problems of transport and pollution, then Tuen Mun will be, by Hongkong standards - and even by any standards, satisfactory.'' Despite its darker sides, Sir David was adamant that Tuen Mun had many ''good things'': impressive sports facilities, its town hall, and strong community spirit. If there was one factor which blighted the town's development, according to the current Housing Authority chairman, it was not due to the planners. He said a turning point was in 1980, when the Government lost a legal battle which freed farmers from land-use constraints. This led to the explosion of container storage on what used to be agricultural land, especially around Yuen Long. In turn, more and more container vehicles took to the Tuen Mun Highway, polluting the air and clogging up the town's main artery. District Board chairman Mr Lau Wong-fat said the board worried that transport problems would worsen if the Government pressed ahead with low-density housing and port projects. He accused the Government of giving Tuen Mun second priority in terms of allocation of resources. But for now, it seems Tuen Mun needs more than money. Like all the world's concrete jungles, where community spirit is breaking down and residents fear to walk the streets at night, it needs to be re-invented in its original image. Whether the authorities have the answer, or the willpower to make the model new town work, is anyone's guess.