UCL Department of Economics


'Should cannabis be legalised?' - new Economics film launched online

28 June 2012


The policy of ‘depenalising’ cannabis in Lambeth between 2001 and 2002 – where people with small quantities of cannabis were given a warning instead of being arrested – led to an 8% fall in overall crime in the area. That is the main finding revealed by a new documentary, 'Should Cannabis Be Legalised?', now available free online:

The documentary, by production start-up Econ Films, focuses on a study by economists Jérôme Adda, Brendon McConnell and Imran Rasul on the effect of depenalisation on crime presented at the recent Royal Economic Society annual conference. Their research compares crime records for Lambeth with all other London boroughs between 1998 and 2006.

The documentary reports that:

* Crime rates for cannabis possession went up by around 20%.

This more than offset the fall in cannabis arrests because of the change in policy. Moreover, cannabis possession was still higher well after the policy experiment ended. By looking at the neighbouring boroughs, the researchers estimate that a large chunk of this increase (as much as half) was due to people coming from nearby to buy and smoke cannabis in Lambeth – so-called ‘drug tourists’. The rest of this rise is caused by a combination of a) cannabis users buying more cannabis, b) new people starting to using cannabis, and c) police reporting arrests where they would otherwise not have done.

* But other sorts of crime fell by 11%.

Other crime fell by 11% compared with the London average and overall crime fell by 8% (due to the rise in cannabis possession offences). Crime fell in areas such as violence against the person, sexual offences, robbery, theft, fraud, and criminal damage – these account for 97% of crimes in Lambeth. Meanwhile arrests went up by around 3% and prosecutions also went up. As Imran Rasul puts it: ‘this suggests there is an increase in police effectiveness’ – just as the policy had intended.

* House prices in Lambeth were 6% lower than they otherwise would have been.

House price data from the time shows that, despite the fall in crime, Lambeth became a less attractive place to live. So although there was public support for the scheme, there was a case of ‘not in my backyard’.

The documentary argues that this ambivalence towards cannabis can help explain why cannabis is still illegal in the UK despite the growing calls for a change in approach.