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Fact Check: do the police spend over a million hours a year fighting cannabis?

Counting the cost. Shutterstock

One million police hours fighting a cannabis market that is out of control. Time to regulate it.

Nick Clegg, former Liberal Democrat leader, commenting on Twitter on May 15 on the party’s election pledge to legalise cannabis.

According to the authoritative Crime Survey for England and Wales, 6.5% of 16 to 59-year-olds use cannabis. But fewer people are using cannabis than in 1996, when information first became available.

While much of the debate surrounding cannabis use has focused on the extent of potential harm to users, recently demands for a change in the law have focused on the benefit to the criminal justice system that legalisation might deliver.

The Liberal Democrats claim that a legal, regulated market for cannabis will save 1.04m police hours annually (just over half of this they calculate is spent on supply). Their calculations – which they shared with The Conversation – are based on Ministry of Justice (MoJ) figures of police caseloads for drug offences in 2015. They also use Treasury estimates of the number of hours police officers of different ranks (constable, sergeant or inspector) need to spend per case of cannabis possession or supply (updated from a thorough Institute for Social and Economic Research (ISER) study). The graph below shows the amount of time spent across officer ranks on each outcome for possession or supply of cannabis.

Cannabis is a Class B drug in the UK, possession of which can lead to five years in prison and an unlimited fine or both. Supply and production can be punished with up to 14 years in prison and an unlimited fine or both. In practice, and based on MoJ 2015 figures, three quarters of a total of 75,207 cases of cannabis possession are dealt with by warnings (51%, including khat), penalty notices (11%) or cautions (13%). By contrast, 81% of all Class B drug supply arrests end up in court.

Data on the amount of actual police time spent fighting cannabis supply, however, are fuzzy. Treasury estimates do not differentiate between the time spent by police on cautions and preparation for court. The MoJ police caseload figures (which list 12,040 cases in 2015) also refer to the supply of all Class B drugs, not just cannabis. Nevertheless, if supply cases are comparable to possession, cannabis should account for around 84% of Class B drugs supply – or a little over 10,000 cases.

The Liberal Democrats also propose that they “will make cannabis safer by limiting THC content” – the drug’s psychoactive element. The ISER and Treasury studies suggest the limit could be set at 10%, but after legalisation there would still be an illicit trade in cannabis over this limit and, as happens with cigarettes, for cannabis under this limit to still be sold on the black market. So the police will need to remain active to enforce the regulatory regime, as well as policing the supply and possession of higher potency cannabis, including skunk, which would remain illegal and according to the Home Office Cannabis Potency Study 2008 dominates the market. These factors would be expected to reduce the proposed savings on police time.

Because it is currently unknown how much time exactly the police spends fighting cannabis supply (rather than all Class B drugs) and because, even after cannabis legalisation, a large part of the illicit market for the drug is likely to remain, the Liberal Democrats’ alleged savings of just over half a million hours in relation to supply offences (precisely 553,840 hours, calculated as 12,040 caseloads multiplied by 46 hours) are overly ambitious. Indeed, reasonably expected savings from releasing police time from supply offences for cannabis under 10% THC content may be completely offset by the additional demands triggered by cannabis legalisation.

In the last ten years, 15% to 25% of the cannabis possession police caseloads ending in cautions and court preparations refer to under 18-year-olds.

As the Liberal Democrats would still need to police the use of cannabis by this age group, their calculations, based on all caseloads, are already overestimated by 50,414 hours, the time the police spent in 2015 dealing with under 18-year-olds. This is the sum of 21,310 hours for 2,130 cautions and 29,104 hours for 1,819 court preparations for non-adults.

Following legalisation of cannabis use for adults, however, the proportion of under-18s who are cannabis users may decrease. This expectation is in line with examples from the effect on under-18s of policy initiatives on banning smoking or alcohol consumption.

Post legalisation, however, overall demand for cannabis is expected to rise by between 9% and 24%. There is also evidence of a link between cannabis use and shop-thefts, other acquisitive crimes and violence. Greater cannabis use will also likely increase alcohol consumption and arguably alcohol–related offences.

There is mixed evidence, however, about the role of cannabis as a gateway drug for harder drugs but, if confirmed, cannabis legalisation may lead to a rise in still illegal harder drug use and associated offences. All these will pose additional demands on policing in indirect ways and further reduce savings on police time.


The police spent nearly a million hours fighting cannabis in 2015, on the assumption that cannabis supply caseloads accounted for 84% of all Class B drug offences. A regulated and licensed cannabis market will definitely release police time with regards to enforcing possession of low potency cannabis.

But the overall 1.04m police hours the Liberal Democrats claim would be saved in police time by legalising cannabis is vastly overestimated because of the questionable estimates relating to supply offences. Discounting the 553,840 hours the police spent in 2015 enforcing the supply of Class B drugs offences – time which would still, at least in part, be required to regulate the sale of low potency cannabis and enforce the ban on the supply and possession of high potency versions of the drug – and the 50,414 hours spent policing cannabis possession among under-18s, which would also remain illegal, the hours potentially saved total under half a million.

There are, however, other potential positive policy outcomes from legalisation, such as a predicted fiscal benefit from tax revenue of between £541m and £768m – and overall savings to the health and criminal justice systems predicted at anywhere between £19m and £71.6m by the Treasury and ISER. The full extent of the reduction in police time arising from the legalisation of cannabis, however, is still very much open to conjecture.


James Mehigan, lecturer in criminology, Open University

This is a logical and fair discussion of the available data on this topic. The point the Liberal Democrats are making, that in a legalised-cannabis- world police would have more time to deal with more serious offences, is a strong one. But quantifying exactly how much extra time they would have in such circumstances is fraught with difficulty. It is right to say that any form of legalisation will inevitably leave some cannabis criminalised and therefore subject to regulation by the police. This regulation will use up at least some of the freed hours. The Lib Dems have chosen a figure for freed hours at the high end of the scale and while the data doesn’t neatly allow us to be precise about the figures, the author’s calculation that it would be significantly lower is reasonable.

The question may be slightly bigger than just police hours, however. Possession of cannabis is a gateway offence that often introduces young people to the criminal justice system and its many deleterious effects. Legalising it may alleviate pressure on other aspects of the criminal justice system (such as probation) and allow young people to more effectively enter the jobs market without the stigma of a criminal conviction. The economic impact of this cannot be measured in the abstract.

The Conversation is checking claims made by public figures and in the public domain. Statements are checked by an academic with expertise in the area. A second academic expert then reviews an anonymous copy of the article. Please get in touch if you spot a claim you would like us to check by emailing us at Please include the statement you would like us to check, the date it was made, and a link if possible.

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