Background Moving on from high secure psychiatric care can be a complex and potentially stressful experience, which may hinder progression. A leavers' group in a UK high secure hospital is offered to support patients with this transition. Aims The aims of this study are to investigate characteristics of patients referred for the leavers' group and compare outcomes for leavers' group graduates with those for patients who never attended a leavers' group for any reason. Methods A retrospective quasi‐experimental design was applied to data extracted from various records sources – within and outside the high security hospital. Results About one‐fifth of patients who left the hospital on trial leave during the study were referred to the leavers' group (N = 109). Referred patients were significantly more likely to have either been admitted from another high‐security hospital or transferred from prison for treatment and have a diagnosis of paranoid schizophrenia. Patients not referred had a significantly higher rate of previously refusing to participate in groups. There was a tendency for rate of return from trial leave for group graduates to be lower than that of patients who did not attend the leavers' group, but this just failed to reach statistical significance (rate ratio [RR] = 1.04; CI 0.97–1.11). Conclusions A leavers' group appeared to be a valued therapy option for people who had spent a long time in high secure psychiatric care, or those who continued to require hospital treatment beyond prison tariffs. There was a low return rate from trial leave, which made the evaluation of this outcome difficult. A detailed study into both the reasons for return from trial leave and successes would provide further information on ideal preparation for moving on. Copyright © 2016 John Wiley & Sons, Ltd.