Earlier this week, police stormed Zurich's infamous `needle park'. The dealers had fled, but the problem remains. Mike Huggins reports
The number 11 tram runs through the heart of Zurich's banking district. Its green paintwork looks as if it were freshly applied every morning before being presented to the city's inhabitants. Inside, there is no graffiti, none of the seats have been slashed and all the passengers wear stylish clothes.

On an average day, hundreds of millions of dollars tumble through accounts in banks along the Bahnhofstrasse, Zurich's exclusive shopping and banking centre. The street glitters with gold-plated signs and huge glass frontages. The hilly alleys running off the street house cosy restaurants, exclusive boutiques and delicatessens.

Unlike similar districts in other European cities, the Bahnhofstrasse is not just the preserve of the wealthy. In Switzerland, the majority can afford to shop here; almost everyone has a high disposable income. Remove the banking giants and Bahnhofstrasse is not too different to the rest of the city.

But about a kilometre awayis another side to the city. It is called Kornhausbrucke, after the bridge that runs over Letten, a disused railway siding. Since 1992, when police closed down Zurich's notorious "Needle Park", the Platzpitz Park, behind the main railway station, Letten has become a haven for heroin addicts.

Last summer, up to 4,000 addicts from all over central Europe gathered there to shoot up at what had become an open-air drugs bazaar. Junkies from 15 to 60 could be seen sharing syringes and lying comatose in pools of vomit. Some wore rags while others prepared their concoction in suits and ties.

"When it rained, it looked like a slum in a developing country," says one social worker at a needle-exchange centre. "The people looked like the living dead, pale and completely out of it."

For three years, the police and cantonal authorities tolerated the junkies and dealers at Letten. It was more secluded than previous drug haunts and an area where the normal Zuricher would never venture. But last summer the number of addicts and dealers mushroomed. Residents complained of finding bloody syringes on their doorsteps, tabloid newspapers carried reports of kindergarten children being offered heroin by dealers. Even the country's biggest supermarket chain, Migros, threatened legal action for loss of trade at its local branch.

The crunch came after gang warfare erupted among dealers competing for turf. Many had entered the country as refugees from Lebanon and former Yugoslavia, and found their weekly state allowance too little to live on. One man was knifed, two shot in the head at point-blank range, and a Lebanese youth was shot in the back. Schools erected high fences and employed security guards - not uncommon in the United States, but unacceptable in Switzerland.

Under unprecedented pressure from residents, cantonal and city officials huddled in a closed-door meeting late last year to plan decisive action.

The outcome was that Letten would be closed: illegal foreign addicts and dealers would be deported, Swiss violators would be packed off to their home communities for treatment, and an increased police presence would remain to prevent a similar scene developing elsewhere.

Over the past 25 years, the authorities have battled, and repeatedly failed, to suppress Zurich's illegal open drug trade. Switzerland's relative isolation from the rest of Europe has meant only a few dealers have been able to import drugs, keeping competition under control and prices down. In Zurich, the problem had reached epidemic proportions - low prices combined with the relatively easy availability of high-quality hard drugs, attracted users and dealers from all over the Continent. When the Swiss authorities cracked down on the Platzpitz Park in 1992, workers had to remove the top two metres of soil to get rid of all the syringes.

Government statistics suggest there are about 32,000 regular heroin users in Switzerland. Social workers say the figure is much higher and could include almost 1 per cent of the country's six million inhabitants. Switzerland spends about 500 million francs (£258m) annually fighting its drug problem, a large proportion of which is spent on enforcing the anti-drug laws. Military force is applied to detain suspects and deport foreigners arrested for drug offences.

"We are the richest country in Europe and perhaps the world and we have a high level of social control. There are no niches for those who don't fit in, no structure for those who can't make it," says Dr Andre Seidenberg, who works at Zurich's ZOKL II polyclinic, where about 50 addicts receive heroin under a strict, medically supervised programmme. So far, the government has been reluctant to extend the programme to all addicts. Only 1,000 addicts benefit from the scheme nationally, most of whom have been injecting for five years or more.

On Monday night, more than 300 riot police, armed with pump-action rifles, plastic bullets and tear gas swarmed into Letten. The area was fenced off, but much to the disappointment of the 200-plus journalists and camera crews, there was not an addict or dealer to be found, and unlike in previous actions, there was no violent confrontation with demonstrators. All that remained was a blanket of used syringes and bloody swabs.

Social workers say that most of the addicts had gone underground after stocking up enough supplies to last until the police surveillance cools off. Many, forewarned of the imminent police action, or deterred by the cold weather, had left town. In nearby Langstrasse, the city's red-light area, however, addicts could be seen shooting up in doorways and alleys.

For many Swiss, the closure of the Letten area marks the end of an open drugs scene that was the source of deep shame. But social workers and doctors claim the country's repressive policy on drugs will be counter- productive. "Until the authorities and people of Switzerland examine why we have this problem and start addressing the causes, it will always continue in some shape or form," argues Mr Seidenberg.

The Association of Drug Specialists had warned that the closure of Letten would merely force addicts to regroup elsewhere or go underground. Pointing to the example of the Platzpitz Park, the organisation's president, Vigeli Venzin, says prices will rise and the quality of the drugs will fall as the drugs scene is driven underground. As a result, he says, the health of addicts will suffer, and the temptation to share needles grow, thus increasing the risk of Aids.

Under new measures that won overwhelming support in a referendum last year, police now have the power to search, arrest and detain anyone suspected of living illegally in Switzerland. Police hope these "anti- foreigner" laws will help them crack down on drug abuse The laws became effective at the beginning of this month and coincided with the opening of a new 120-bed prison for foreigners suspected of committing an offence. Under the law, a foreigner can be held in jail for up to a year without trial while waiting to be deported. Another prison is scheduled to open before the end of the year.

Whether these punitive policies will actually solve the city's drug problem remains to be seen. In the meantime, Zurich residents are wondering nervously whose neighbourhood will become the next "needle park".