This thesis focuses on Looked After children and young people, exploring issues in relation to effective psychological intervention and measurement of mental health difficulties within this population. Section one of the thesis is a systematic literature review which aimed to identify and appraise the standardised tools that have been used to measure mental health within populations of Looked after Children. Measurement of mental health within this population can be varied and inconsistent, with a wide range of standardised tools being used from the general child and adolescent population. While the review identified the use of several tools, the majority were lacking in evidence of sound psychometric properties for use within this population, limiting their clinical utility. Caution and further investigation is advised. The empirical piece of the thesis describes a feasibility study of a recently developed group intervention programme for parents and carers of looked after and adopted children. Entitled 'Nurturing Attachments', the programme is intensive and group based and focuses on supporting carers to therapeutically parent the children in their care. Nurturing Attachments was delivered for the first time in Northern Ireland as part of this study, which aimed to assess feasibility through exploring recruitment, retention and attrition, initial outcomes, acceptability and the ability of the programme to be delivered as outlined in the programme manual. Findings showed that this intervention is feasible, having positively impacted on many levels of the care system.