The UK Department of Health's Rolleston Committee Report[34] in 1926 established the British approach to diamorphine prescription to users, which was maintained for the next 40 years: dealers were prosecuted, but doctors could prescribe diamorphine to users when withdrawing. In 1964, the Brain Committee recommended that only selected approved doctors working at approved specialized centres be allowed to prescribe diamorphine and cocaine to users. The law was made more restrictive in 1968. Beginning in the 1970s, the emphasis shifted to abstinence and the use of methadone; currently, only a small number of users in the UK are prescribed diamorphine.[35]

In 1994, Switzerland began a trial diamorphine maintenance program for users that had failed multiple withdrawal programs. The aim of this program was to maintain the health of the user by avoiding medical problems stemming from the illicit use of diamorphine. The first trial in 1994 involved 340 users, although enrollment was later expanded to 1000, based on the apparent success of the program. The trials proved diamorphine maintenance to be superior to other forms of treatment in improving the social and health situation for this group of patients.[33] It has also been shown to save money, despite high treatment expenses, as it significantly reduces costs incurred by trials, incarceration, health interventions and delinquency.[36] Patients appear twice daily at a treatment center, where they inject their dose of diamorphine under the supervision of medical staff. They are required to contribute about 450 Swiss francs per month to the treatment costs.[37] A national referendum in November 2008 showed 68% of voters supported the plan,[38] introducing diamorphine prescription into federal law. The previous trials were based on time-limited executive ordinances. The success of the Swiss trials led German, Dutch,[39] and Canadian[40] cities to try out their own diamorphine prescription programs.[41] Some Australian cities (such as Sydney) have instituted legal diamorphine supervised injecting centers, in line with other wider harm minimization programs.