<Li> Supplying or offering to supply a controlled drug (even where no charge is made for the drug) </Li> <Li> Allowing premises you occupy or manage to be used unlawfully for the purpose of producing or supplying controlled drugs </Li> <P> It is often presented as little more than a list of prohibited drugs and of penalties linked to their possession and supply . In practice, however, the act establishes the Home Secretary as a key player in a drug licensing system . Therefore, for example, various opiates are available legally as prescription - only medicines, and cannabis (hemp) may be grown under licence for' industrial purposes' . The Misuse of Drugs Regulations 2001, created under the 1971 Act, are about licensing of production, possession and supply of substances classified under the act . </P> <P> The act creates three classes of controlled substances, A, B, and C, and ranges of penalties for illegal or unlicensed possession and possession with intent to supply are graded differently within each class . The lists of substances within each class can be amended by order, so the Home Secretary can list new drugs and upgrade, downgrade or delist previously controlled drugs with less of the bureaucracy and delay associated with passing an act through both Houses of Parliament . </P>

What is the purpose of the misuse of drugs act 1971