The undersecretary for security says he is satisfied that 61 per cent of pupils in Tai Po are willing to join a voluntary drug-testing scheme. Lai Tung-kwok said on a Commercial Radio programme yesterday that the remaining pupils had opted not to take part in the scheme for various reasons, but this did not mean they objected to drug testing. 'This is the first time a drug-testing scheme has been run and the scheme is voluntary,' he said. 'There has been both positive support and opinions about how to improve the scheme. We have not denied this point. 'I hope through the implementation of the scheme, those pupils who have not taken part in it will get the drug-free message.' Lai said he did not think the Security Bureau would assume that pupils who were unwilling to take part were drug users. He added that people should not rely only on the government in the campaign against teenage drug use. 'The government has the responsibility to get the drug-free message across to youth, but we also need to deploy the power in the community,' he said, referring to NGOs. A school drug-testing scheme was needed to help teenagers understand the problems of drug abuse because the situation had been worsening, Lai said, with the number of drug users under 21 increasing by 57 per cent in the past four years. He also showed appreciation for organisations that used a gentle approach to teenage drug users. He said he had joined a team of social workers in making contact with teenagers loitering late at night on a football pitch in Mong Kok two weeks ago. The social workers used instruments to test how dry the teenagers' skin was, an indicator of drug use, and those with unusually dry skin were referred to doctors for body checks. 'That was very popular with the teenagers,' Lai said. 'The teenagers referred for body checks might tell doctors about their drug abuse problem.'