The Dame Carol Black Review of Drugs Part 1 contains an estimate of the total cost of harms related to illicit drug use in England of £19.3 billion in the financial year 2017/18. This was published in February 2020: Review of drugs: phase one report - GOV.UK (www.gov.uk)
This estimate includes costs associated with the demand side of the drug market including healthcare and treatment costs, as well as costs associated with acquisitive crime. Therefore, these cost estimates capture wider costs than those purely relating to drugs supply.
A corresponding estimate is not currently available for Wales.