Antidrug legislation in the U.K. dates from the 1920 Dangerous Drugs Act, with subsequent drug control laws passed in 1933 and during the 1960's. The most recent, Misuse of Drugs Act (1971), is yet to be fully implemented. It intends to replace former piecemeal legislative attempts to deal with new and previously unexperienced drug abuses by confronting new patterns of drug abuse as they arise and providing penalties for drug offenses according to relative harmfulness of different drugs. The act distinguishes between possession and trafficking and provides the Home Secretary with more flexible controls over the professional prescribing of a wider range of drugs without the need for new legislation. The dominant changes in drug abuse noted in recent decades were the increase in cocaine and heroin addiction among the young as well as widespread misuse of amphetamines and barbiturates. Control efforts invoke the cooperation of the medical profession in curbing prescriptive practices conducive to addiction. The British system of responding to addiction as a form of illness rather than a type of deviant or criminal behavior has operated since the 1920's with criteria for prescribing drugs to addicted persons; most recently this practice involves special government clinics where those dependent on opiates can obtain drugs prescribed for them. Recent British drug policies have been shaped by studies of the Standing Advisory Committee, which has produced reports since 1967 on cannabis, amphetamines and LSD, and police arrest and search practices. A similar multidisciplinary committee will continue to work under the new law. The role of law enforcement regarding simple possession remains an issue to be resolved. Provisions of the Misuse of Drugs Act are appended.