"Latest national and regional estimates for England are for 2009/10 for opiate and/or crack cocaine use, with separate estimates available for opiate use, crack cocaine use, and injecting drug use. In Scotland, the latest national and regional estimates for problematic opiate and/or benzodiazepine use are also for 2009/10 and were published in 2011. Drug injecting estimates for Scotland are available for 2006. In Wales, local and national estimates for 2009/10 for long duration or regular use of heroin, other opioids, crack cocaine and/or cocaine powder were published in 2011. Estimates for Northern Ireland for 2004 were published in 2006 and cover problem opiate and/or problem cocaine powder use.
"Based on these, it is estimated that there are a total of 383,534 problem drug users in the United Kingdom, and 133,112 people who inject drugs (PWID) (primarily opiates or crack cocaine)."

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. 84.
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