It has been long recognised that there is an over-representation of those with severe mental illness (SMI) interacting with the Criminal Justice System (CJS). Consequently, those who work with people with SMI are likely at some stage to find themselves interacting with and receiving requests to share information by different authorities to inform the justice process (before, during and after) as well as to facilitate multi-agency risk management structures in the community. In this chapter we briefly review the policy context and development of Liaison and Diversion systems within England and Wales for both adults and young people. Following the pathway of a mentally disordered offender being arrested by the police, we describe the medico-legal frameworks whereby mentally disordered and increased-risk offenders can be dealt with by the courts and managed in the community. We also consider the particular differences that pertain when the individual is a child or young person (CYP), and broader fora wherein information sharing occurs for the purpose of public protection in the community context, especially within MAPPA and PREVENT panels. We also note the use of the National Referral Mechanism.