"While the number of convictions (at court or cautions) for cannabis possession in 2010 (n=59,750) is 26% lower than in 2003 (n=80,656) before the introduction of the formal warning for cannabis271 in England and Wales, the number has increased by 24% since 2007 (n=48,299) (ST11). This suggests that more punitive sanctions are being used to deal with cannabis possession offences. Data from England and Wales show that there was a seven per cent increase in cannabis possession offences dealt with by a caution or in court between 2009 and 2010 with a corresponding seven per cent decrease in the use of non-criminal sanctions such as the formal warning for cannabis and the penalty notice for disorder272 (Figure 9.1). Although the total number of cannabis possession offences dealt with by law enforcement (either through criminal or administrative measures) decreased between 2009 and 2010 (from 154,336 to 150,765), the number remains almost twice as high as before the introduction of the formal warning for cannabis (n=77,500). This is despite a decrease in reported cannabis use over the period (see section 2.2 and Trends Analysis section)."

Source

UK Focal Point on Drugs, "United Kingdom Drug Situation 2012 Edition: Annual Report to the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA)" (London, England: UK Government, Department of Health, October 31, 2012), p. 153.
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