Nitrous oxide is covered by the Psychoactive Substances Act 2016, meaning it is illegal to supply – note that money does not have to change hands for this to happen – or produce for its psychoactive effect, but not possess. Confusingly, it is available to purchase, as it has uses in the catering industry, and is widely used medically as an anaesthetic: “gas and air” is nitrous oxide mixed with oxygen – an important distinction to how it is used recreationally – commonly used during childbirth and in emergency trauma situations.

According to NHS England data, in 2018 nitrous oxide was the third most common recreational drug used by 11-15-year-olds, exceeded only by cannabis and volatile substances such as glue, gas, aerosols or solvents.