As the UK’s heavily-derided ‘legal highs’ ban takes effect, prisoners found in possession of these substances will face the prospect of an increased sentence, while the general public receive no criminal record for the same offence.

The Psychoactive Substances Act (PSA), described by civil society groups as “unworkable, unwieldy, and [likely to] increase health and social harms”, comes into force today, nearly two months after the proposed start date of April 6.

Employing deliberately broad language, the PSA bans the production and supply of anything that “is capable of producing a psychoactive effect in a person who consumes it”, as the government tries to knock out the market for ‘legal highs’, or new psychoactive substances (NPS). Exemptions are provided, however, for the nation’s most used legal psychoactive drugs: alcohol, tobacco, and caffeine.

The PSA has endured ridicule from political commentators such as Ian Dunt, who described how anyone found to be selling perfume or flowers could face seven years in prison thanks to the Act’s broad definition of “psychoactivity”. The Home Office has seemingly tried to refine this definition in their official guidance issued prior to the PSA’s commencement.

Another of the Act’s curiosities appears to have slipped by largely unnoticed, though. Prior to being given Royal Assent in January, the then-Bill was amended at the House of Commons second reading to criminalise the possession of NPS by anyone “in a custodial institution”, meaning prison inmates can face an extension of their sentence of up to two years and/or a fine if caught in possession. This is despite possession not being a criminal offence for the wider population.

The amendment – which also allows for incarcerated juveniles and detained refugees to face harsher penalties than the general population - was introduced by Mike Penning MP, the Minister of State for Justice, who oversaw the passage of the bill.

Steve Gillan, the general secretary of the Prison Officers’ Association, partly attributed NPS use to the 37 per cent rise in attacks on prison staff that has occurred over the past year, claiming the drugs “alter people’s state of mind”. Increased violence and deteriorating mental health among prisoners have been widely publicised in the media - often with the use of inflammatory language - as being resultant of NPS use. Despite such testimonies, Mike Penning’s amendment did not call for improved mental health services for prisoners who may need them. Nor did it request the introduction of measures to protect prison staff from violence. Instead, Penning suggests that strictly punishing and marginalising all those who possess NPS will “complement the continuing work […] to educate prisoners […] about the harms”.

National drug policy is no longer part of Penning’s work portfolio, instead being within the remit of Karen Bradley MP - the Minister for Preventing Abuse, Exploitation and Crime – who lauded the PSA as part of a strategy to “eradicate this abhorrent [NPS] trade”. Yet, neither Penning’s nor Bradley’s comments on the best measures to tackle drugs seem to square with findings from a 2014 Home Office study that concluded that “there is no apparent correlation between the ‘toughness’ of a country’s approach and the prevalence of adult drug use”.

Furthermore, this legislation diverges from an assertion made by the Home Office, under the leadership of Theresa May, that the government intends to improve its prison-based treatment services to support “sustained recovery from addiction”. Instead, the PSA vows to punish prisoners who use drugs. The nature of the punishment – forcing them to remain in an environment in which almost 80 per cent of people have used illegal drugs – undoubtedly reduces the government’s ability to achieve its purported agenda of supporting “sustained recovery”.