To provide specialist assessment of adults within Specialist Weight Management Services (SWMS) utilising information from a range of standardised psychometric tests, case history and clinical interview and integrating it into a formulation of the client and the psychosocial environment drawing on a range of psychological perspectives. To undertake a range of evidenced-based psychological interventions, drawing on a range of psychological models and employing a range of modalities (individual, family and group) adapted and tailored to the needs of the individual and the context and the ongoing evaluation of the outcomes of the intervention. To formulate and implement plans for the formal psychological treatment and/or management of a clients condition, based upon an appropriate conceptual framework of the clients difficulties, and employing methods based upon evidence of efficacy, across the full range of care settings. To evaluate and make specialist decisions about psychological treatment options taking into account both theoretical and therapeutic models and highly complex factors concerning historical and developmental processes that have shaped the individual, family or group in the context of bariatric surgery.