The details of a pilot scheme for drug testing in schools have been revealed. Authorities hope to use what they glean from the scheme in Tai Po as the basis for a city-wide programme. They believe such testing will curb the growing youth drug problem and act as a deterrent. Their heart is in the right place, but the idea is flawed. Education Secretary Michael Suen Ming-yeung clearly does not think so. He would not be devoting valuable resources to the scheme if he thought otherwise. The cost was not revealed yesterday, nor was it certain how many schools would participate. What is clear, though, is that the idea has been rushed and not thought through. Drug testing is expensive. Even when no cost is spared - as with professional sportspeople - the results are open to question. There is also a need to consider the consequences and complications. And testing does not get to the root of the problem of why our children are turning to drugs or why they can so easily get them. Police have long expressed concern about drugs. The government was to have had a consultant look at the feasibility of testing in schools next year. But a series of cases and police figures showing a marked upward trend among young people spurred Chief Executive Donald Tsang Yam-kuen to fast-track trials. The process will get under way next month among schools in Tai Po. Parents will voluntarily sign up children. Three months of education will take place before six months of testing begins in December. An external five-member team will visit two schools each day, randomly choosing 20 students from each for testing. A school will have 40 students tested every month. Students chosen can refuse to participate, but will be interviewed by a social worker. Urine samples will be taken unobserved and the student will be present when results are being processed. Those with a positive result will be put into a counselling programme. Police will be called in if information of a serious nature is revealed. Procedures will be changed if found not to be working properly. There are a host of potential problems which are plain from programmes elsewhere with a long track record. Urine is the least reliable way of catching a student out - it can be substituted or tainted by other liquids or medication. Mr Suen all but acknowledged this, saying the aim was to test hair samples but that the facilities for this were not yet available. Some commonly used drugs, such as Ecstasy and methamphetamine, stay in the body a matter of hours and can easily go undetected. A little internet research quickly turns up ways of getting round drug tests. Then there are the social issues. Students returning a positive test will be labelled. This could prove a badge of honour for some and could increase drug use and hook those who might not otherwise have tried drugs. Students who had only flirted with drugs could be wrongly considered a regular user and put into rehabilitation. Hijacking a learning environment for law enforcement is wrong. Drug testing could well alter students' attitudes towards schools and teachers. A place away from home that could previously have been a place to discuss problems may become off-limits. Teenagers could become more confused and vulnerable to bad influences. Mr Tsang's decision was in large part political. He may be pleasing his constituents by having their children tested for drugs, but has not given sufficient thought to the ramifications. Politics is preventing him from calling off the trial. Hopefully, though, the defects will quickly be apparent and it will be shelved.