HOME OFFICE REPORT ON UK DRUG TRADE
The Guardian article includes a link to the Home Office Report as a .pdf file. The study gives estimates of the number of people involved in the trade and is based on interviews with “222 convicted high-level dealers”.
In case the article is moved, the report can be downloaded directly here (pdf).
There are other reports that have recently come from the Home Office, according to the Guardian, and ACPO is about to hold its annual drug conference, so the newspapers will have quite a few stories over the next few days.