Controlled drugs in the United Kingdom

In the United Kingdom, certain drugs are classified as controlled drugs. Controlled drugs are illegal to possess, use, or supply to others without a license. These drugs are governed under the Misuse of Drugs Act of 1971. This act defines three categories of controlled drugs: A, B, and C. The penalties for illegaly possessing, using or supplying a controlled drug are different depending on which category the drug belongs to. Many of these drugs are also governed by other laws, such as the Medicines Act. Also, there are many other drugs that are not controlled by the Misuse of Drugs Act but that are controlled by other laws.
Class A drugs are drugs that are considered the most dangerous. They carry the harshest punishments. Class C drugs are those that are thought to be much less dangerous. They therefore carry much less serious punishments. More serious punishments are dealt if the person is considered to have had the intention to supply the drug to others. Possession with intent to supply carries a maximum penalty of life in prison.
The laws governing the use and supply of drugs for medical purposes are not part of the Misuse of Drugs Act. A different set of categories apply, which are defined in the Misuse of Drugs Regulations. This sets out five schedules, each with their own restrictions. These restrictions say that a person can possess and use certain drugs if they have the proper prescriptions for them. A prescriptions must be given by somebody who is licensed to provide it (e.g., a medical doctor). The drug itself must be supplied by somebody who is licensed to supply it (e.g., a pharmacy).