Psychoactive Substances Act 2016

The Psychoactive Substances Act 2016 (c. 2) is an Act of the Parliament of the United Kingdom intended to restrict the production, sale and supply of a new class of psychoactive substances often referred to as "legal highs". The bill was given Royal Assent on 28 January 2016, and came into force on 26 May 2016 across the entire United Kingdom.

The law defines as a "psychoactive substance" anything which "by stimulating or depressing the person’s central nervous system ... affects the person’s mental functioning or emotional state". The law bans all such substances but exempts alcohol, tobacco or nicotine-based products, caffeine, food and drink, medicinal products and any drug that is already regulated under the Misuse of Drugs Act 1971.

The Act:

The act also makes those offences punishable by a fine, or by up to a year in prison (six months in Northern Ireland) if convicted as a summary offence, or up to seven years if convicted under indictment. The Act also defines an offence of possession in a custodial institution (prison, young offenders institution etc.) which has the same penalties as the other offences, except the maximum prison term if convicted under indictment is two years.

The Act also describes a series of aggravating factors which judges or magistrates are obliged to consider in sentencing. These are:

In 2015, Home Office minister Mike Penning wrote a letter to representatives of the Roman Catholic Church and the Church of England to try to reassure them that incense would not fall under the jurisdiction of the bill and that churches would not face prosecution for the use of incense during worship.

The Act was due to come into force on 6 April 2016. It was delayed indefinitely due to a lack of clarity as to what the meaning of "psychoactive" is, and what substances are covered by the law. It eventually came into effect on 26 May 2016. The Advisory Council on the Misuse of Drugs also told the Government that alkyl nitrites (poppers) were not covered by the law as they were not considered psychoactive, as they affected the muscles and not the central nervous system. The Government accepted this advice and has stated that poppers are not unlawful under the Act, poppers are not listed as exempted substances in Schedule 1 of the Act; this is unnecessary because of how they do not affect the central nervous system.

In 2017, the Court of Appeal held in Chapman that nitrous oxide was not exempted from the Act as a medicinal product. A subsequent case also concerning nitrous oxide considered whether the inducing of a psychoactive effect (as required for prosecution of offences under the Act) had to be the direct purpose of the substance, or could be an indirect effect. The Court of Appeal concluded that the Act's provisions applied in both situations.