top of page

Drug Policy Explained: Legalisation, Decriminalisation, and Prohibition

Police man stanidng in the road

By Leah Williams 

What is Drug Policy

In law, a policy outlines the rules and guidelines for an act or behaviour. Drug policy explains the different sanctions, criminal or civil, that an individual will face if they break the rules or fail to follow the guidelines around recreational drugs. The government put these sanctions in place in an attempt to deter individuals from using drugs and ultimately reduce drug-related harm incurred by the public.

Drug policy affects us all. From the people who use drugs and the health and social issues they face, to the healthcare workers responding to overdoses and drug related disorders, and the police, courts and probation officers that handle the offender during and after their time in the criminal justice system. Considering the wide impact on public services, it is important to understand the various drug policy models.

Across the globe, the landscape of drug policy is changing. In this article, we hope to explain what the difference is between decriminalisation, prohibition and legalisation, with examples from countries that have adopted alternatives to prohibition such as Portugal and Canada. This article will shed light on the definitions of these terms and what they mean for drug policy. 

Drug Prohibition - The Current Status Quo

In drug policy, prohibition means that some drug-related acts or activities, including possession, production or cultivation, supply and trafficking of drugs are forbidden by law. These acts become illegal and punitive sanctions are put in place for individuals who commit them. 

Prohibition in the United Kingdom

Drug related legislation began in the 1920s with the Dangerous Drugs Act 1920, but drug use was not particularly widespread, although London and the ports in Victoria Britain were known for the infamous opium dens. However, drug use really began to rise in the 1970s, promting the UKs primary drug legislation; the Misuse of Drugs Act 1971.

Dangerous Drugs Act 1920

The Dangerous Drugs Act 1920 outlined how opium, cocaine, morphine, and heroin were to be imported, exported, and distributed. Therefore, the sales of these drugs were regulated and monitored, but no punishment was in place for those who acquired and consumed them.  However, there were punishments for those who sold outside the laws, essentially limiting sales for medical applications. Amendments to this Act were minor but gradually progressive. 

Misuse of Drugs Act 1971

The Misuse of Drugs Act 1971 (MDA) is the UK’s primary drug policy legislation and is still in place today. It criminalises the non-medical use of certain drugs and was the first Act to categorise drugs into classes A, B and C. Class A was characterised as the most harmful and carried the highest punishment (seven years for possession and life for supply) with B and C being relatively lesser. 

Psychoactive Substances Act 2016

As new psychoactive substances, such as synthetic cannabinoids, mephedrone, and 25i-NBOMe, became increasingly popular, new drugs were appearing faster than they could be brought within the MDA (and thus made illegal to sell). Even when they new drugs were banned under the MDA, new versions with minor molecular tweaks would be brought to market rapidly to circumvent the law. The government’s response was to simply ban everything with the Psychoactive Substances Act 2016 (PSA). This Act enforces a maximum of seven years imprisonment for producing or selling any substance that can produce a psychoactive effect. This Act also encompasses ‘legal highs’ derived from food items, plants and various herbs and remedies that produce a psychoactive effect on a person. Caffeine, alcohol, nicotine, and medicine are exemptions from this Act. While the Psychoactive Substances Act did achieve its goal of reducing the prevalence of new psychoactive substances, it did not reduce drug use overall and drug-related deaths have risen year-on-year ever since (including those from NPS!). Many people, who had switched to new psychoactive substances as a safer alternative, simply returned to traditional drugs which were often more harmful. Those who continued with problematic NPS use, often vulnerable people such as users of spice in prisons and the homeless, were pushed into an illegal market.


Both the Misuse of Drugs Act 1971 and the Psychoactive Substance Act 2016 cite criminalisation with an option for imprisonment as their primary penalty, although possession of drugs under the PSA is not criminalised. For possession of the lowest class drug (Class C) under the MDA, an individual will face up to 2 years  imprisonment and an unlimited fine. These penalties increase up to life imprisonment for possession with intent to supply Class A drugs. Whilst it is not an offence to possess psychoactive substances under the PSA, the individual will incur up to 7 years in custody for producing and possessing with intent to supply. However, it is important to be clear that while many people receive cautions or prosecutions for drug possession, incarceration is relatively rare – even if the max sentences appear severe.

Decriminalisation of Drugs

Decriminalisation is to remove criminal sanctions against an act or behaviour. Instead of criminal prosecution, the individual may face civil sanctions such as fines, revoked licenses, or diversion to treatment programmes. By decriminalising drug possession and use, people who use drugs are less stigmatised and may be more likely to engage with treatment services. They are given options and support, instead of a criminal record. It is not just people who use drugs that benefit from decriminalisation. Decriminalisation allows police time and resources to be redirected towards more harmful incidents such as violent crime. Decriminalisation also reduces drug-related harms caused by those attempting to conceal drug use from law enforcement.

Decriminalisation vs depenalisation

Decriminalisation is not to be confused with depenalisation, in which all sanctions (criminal and civil) are removed. With depenalisation, an act remains prohibited and arrestable, but no penalties (criminal or civil) will be enforced. In England and Wales, possession of cannabis is a crime, but the police can issue a written warning instead of arresting the individual. This is done at the discretion of the local Police and Crime Commissioner, creating a ‘postcode lottery’ in which someone could be arrested in Liverpool and Newcastle for the exact same offence, but receive two different penalties. However, it should be stressed that the term decriminalisation isn’t formally defined and is interpreted and implemented in a range of ways

Diversion schemes

Diversion can be thought of as a form of de facto decriminalisation, in that the individual caught in possession will avoid a criminal record. Instead of criminal prosecution, individuals caught in possession  are ‘diverted’ away from the criminal justice system into to drug education, support services or treatment assessments as appropriate . The details of how the schemes are implemented by different police forces can vary considerably.  

The process of diversion is becoming increasingly prevalent in the UK and across the globe.

Some diversion techniques can be seen in Thames Valley Police where drug offenders are offered assessment and treatment services as well as support for social, mental, and housing difficulties. Durham constabulary has a ‘Checkpoint’ system where prosecution is deferred if the offender complies with drug treatment and other support services. Similarly, Avon and Somerset Police offer a ‘Drug Education Programme’ which aims to educate and dissuade young offenders involved in street supply. 

Decriminalisation in Portugal

Portugal decriminalised the use and possession of all illicit drugs in 2001. If you are found in  an illegal drug, you will not face criminal prosecution. Instead, you will be referred to the ‘Committee for the Dissuasion of Addiction’ which consists of a lawyer, psychologist, and social worker. Here, the offender is assessed and if deemed dependent, is referred to treatment centres. Most low-level possession offences see no further action taken, although other sanctions such as fines are reserved for repeat offenders. These treatment centres were made possible by the country’s increased funding into their health service and the realignment of political values, resulting in larger social integration initiatives. 

Prior to decriminalisation, Portugal had deep-rooted, complex drug problems amongst the population. In 2001 and 2002, it had 50% of all new HIV diagnoses attributed to injecting drug use in the EU, despite its population consisting of only 2% of the EU. 

The decriminalisation of drug possession in Portugal, coupled with the increase in health and treatment services available to the public, were followed by a considerable fall in drugs related arrest and imprisonment rates. Moreover, the decriminalisation allowed Portugal to redirect its police powers to address other issues. Drug-related deaths in Portugal remain some of the lowest in the EU, with 6 deaths per million (among people aged 15-64) compared to 23.7 per million on average in the EU (2019).

Drug use in Portugal transformed from a criminal act into a health concern.

Decriminalisation of all drugs in Uruguay

Although not technically decriminalisation, since drug possession was never criminalised in the first place, Uruguay does not have penalties in place for drug use or possession of a ‘reasonable quantity’ for personal consumption. This means that you can consume drugs and possess a ‘reasonable quantity’ – as long as it is for your own use – without facing punishment. 

Legalisation and Regulation of Drugs

Decriminalisation and depenalisation remove sanctions, while legalisation is to make something legal, but regulated by the state.

When something is legalised, the act or activity becomes legal. This means that the act or activity, and the industries which support it, can be more carefully controlled by rules and regulations that must be followed. If these regulations aren’t followed, the person is breaking the law and will face criminal or civil sanctions. If certain drugs were to be legalised, processes and services related to each drug (acquiring, distributing, consuming) would become regulated by the government in the same way as alcohol, caffeine, tobacco, or pharmaceuticals. In addition to greater control of recreational drug markets – such as controls on price packaging and marketing, and licensing of vendors, legalisation has the significant advantage of enabling tax revenue to be generated from drug sales.

Legalisation in action – Alcohol

Let’s take alcohol for example – one of the most popular drugs in the world. Under the Licensing Act 2003, pubs, restaurants, night clubs and other businesses selling alcohol must have the relevant license(s) for the sales to be legal.  There are two licenses awarded by the Home Office: a personal license and a premises license. These licenses will outline rules that the licensee must follow. For example, specific serving/operating hours, Challenge 25, having free drinking water available for customers. If these rules are not followed, the licensee will face possible sanctions e.g., fines or imprisonment.

Legalisation of cannabis in Uruguay

In 2013, Uruguay became the first country in the world to legalise cannabis. The country’s decision to legalise cannabis was described as an ‘intellectual experiment’ that would alienate and exclude large-scale drug traffickers. However, there still remains a controlled regulatory process, licensed distributors, and strict limits on the amount obtainable. Cannabis in Uruguay is effectively a state monopoly, with sales of unbranded potency-controlled products to register adult residents via pharmacies, alongside provision for home growing and cannabis social clubs. Learn more here.

Legalisation of cannabis in Canada

Canada legalised medical cannabis in July 2001 and on 17th October 2018, they legalised it for adult recreational use.  As with alcohol and tobacco, the country regulates the use and distribution of cannabis in many ways and there are safe, designated areas for distribution and consumption. Moreover, cannabis is grown by licensed producers and only sold during certain hours. There remain strong punishments for the sale of cannabis to minors or driving whilst impaired.  

Research shows that the Canadian Government earned C$186 million from tax revenue directly related to the sale of cannabis in the first five and a half months of its legalisation. Tax related to the regulatory and licensing procedures increased 12.4% from 2018 to 2019 and general goods and services tax from the sale of cannabis rose by 68%. Whilst the potential societal strains of a legal cannabis industry should be duly considered, evidence thus far indicates opportunities for economic prosperity and positive impact on criminality, use, and health.  Learn more here.

Keep up with developments in drug science

Reading, engaging with, and sharing our publications, papers and commentary gives evidence-based science and policy the audience it needs and deserves.

bottom of page