In 1992, a trust for the rehabilitation of addicted inmates (RAPt) was established within Downview, a medium-security prison south of London. It includes a 12-step substance abuse treatment program based upon total abstinence and aftercare for inmates to help them achieve recovery and lead full lives upon release. The addiction is most commonly drugs, but may also be alcohol or gambling. The system works on a method of progression, where inmates earn enhanced privileges through good behavior, and work performance. Just as privileges can be earned, they can also be withdrawn. A combination of RAPt procedures, voluntary and mandatory random drug testing, use of a new drug-testing machine, and changes in staff culture and to the prison ethos in general have transformed Downview into a prison that is 96-percent drug-free.