Prince Harry's use of drugs and alcohol has highlighted the widespread problem

And schools and colleges would have to have parental consent for the tests, he added.

The announcement comes as Prince Harry's brush with alcohol and drugs highlighted the problems faced by schools and colleges in the UK in preventing drug misuse among pupils.

The Thai drug-testing plan was announced by the county's Interior Minister, Purachai Piemsomboon, who has introduced a series of measures to enforce "social order" and morality - including cracking down on night life - since he took office nearly a year ago.

Concern for youth

Last year Mr Purachai won widespread public support for enforcing laws to close bars and other entertainment venues early.

Mr Purachai has expressed concern for today's youth after frequent reports that night-spots had lured young people into a lifestyle of illegal drugs and promiscuous sex.

In Thailand, one of the main social problems is the trafficking and consumption of methamphetamine, a cheap illegal stimulant in ready supply.

Mr Purachai said the details of the drug testing, which would cover university students, would be finalised later this month.

UK drugs testing

In the UK, testing pupils for drug abuse has proved a difficult area.

According to Bob Carstairs, assistant general secretary of the Secondary Heads Association, attempts by state schools to use drug testing to identify users have not been successful.

Concerns about the ethics of testing young people and doubts over whether pupils could be forced to take tests were the main problems.

Mr Carstairs said the expense of testing was another reason that it had not become widespread.

The Independent Schools Council says some private schools require drug tests from pupils who have been caught using drugs.

This testing can be a condition of allowing the pupils to remain in the school.

At Eton, where Prince Harry is studying for his A-levels, boys can be subjected to urine tests or other drugs tests - which is usually done only when there is reasonable cause to suspect they have been using drugs.