On the 1st of April 1999 Somerset Health Authority and Somerset County Council established a Joint Commissioning Board (JCB) to commission mental health services. Simultaneously, the Somerset Partnerships Health and Social Care NHS Trust was set-up as a combined health and social care services provider; for the first time in England, the majority of social services mental health staff transferred their employment to this Trust. The JCB commissioned an evaluation of the impact of these innovations on users and carers, staff and senior officers and members in the organisations concerned.