The general public, police, service providers, and users/ex-users were asked their views about options for trial design and trial outcomes with regard to a proposal for experimental controlled heroin availability. There was substantial agreement between the samples on issues concerning trial design. In general, the samples from the community, service providers and users/ex-users were more likely to report that a trial would result in positive outcomes, whereas the police sample was more likely to report that a trial would result in negative outcomes. This study illustrates the value of systematic consultation of key groups in exploring the options for change, raising potential difficulties, and highlighting different interests.