Diversion is a significant problem in my own town of London. I've witnessed it myself.
When patients have been given a daily dose of their medication in the pharmacy, they take it out and then are swarmed immediately by people on the street. They sell what they're meant to be taking for the balance of the day. Increasingly, there are a lot of younger people coming into the clinic seeking treatment for the management of their opioid dependence. This invariably started as a result of accessing street drugs in the form of hydromorphone, which had obviously been diverted.
