The total number of reported drug abusers in that period had risen 15 per cent to 17,000, while the number under 21 had grown to 3,000, Mr Patten said.

'While we can be reasonably certain that the problem of drug abuse would have been even worse had we not had an extensive programme of preventive education and publicity, recent surveys show an alarming ignorance of the risks of taking drugs, particularly psychotropic substances.

'The coverage and efficiency of our education effort is clearly deficient,' Mr Patten said.

The Government was planning to expand the Hospital Authority's treatment services for psychotropic substance abusers. It was also establishing a new counselling centre and two more residential treatment centres for young drug abusers.

On the law enforcement front, the Department of Health was increasing the number of pharmacy inspectors. A special taskforce would be formed to help prosecute offending drug retailers.

Mr Patten said he would chair a summit conference next year with schools, parents and non-governmental organisations to plan a community-wide education and support effort to try to halt the growing trend for drug abuse.

But the head of the Hong Kong University Drug Addiction Research Unit, Dr Jeffrey Day, said the Government would have to consider decriminalisation of drugs.

'I'm talking about all drugs because the harder the drug, the more profit there is to be made out of it if it is a criminal drug. On the other hand the harder it is, the more careful the control has got to be if we are going to get involved in decriminalisation,' he said.

Dr Day said decriminalisation was an issue which had to be discussed as a reasonable alternative.

He said there was an enormous drain on the judicial system and economy, given that many millions of dollars were spent by known existing heroin abusers annually.

'We have an enormous profit nature which leads people to push drugs, if there is no profit in selling drugs then there is no point in pushing them to that degree,' he said.

'The whole community must understand what decriminalisation is all about and the young particularly must understand that this is not a free-for-all on drugs before we can even begin to consider it as a reality.' The Commissioner for Narcotics in the Security Branch, Alasdair Sinclair, said the increase in the use of drugs among people under 21 was alarming.

He said the concept of decriminalisation needed to be more clearly defined, but even in the context of cannabis he did not consider it to be an appropriate action.

He said the public outcry when the suggestion of decriminalisation was made by two senior judges showed there was no way the people of Hong Kong would accept it.