The theory of attachment, proposed by Child Developmentalist John Bowlby, has been one of the most successful paradigms introduced to psychology, with the core hypotheses being widely supported (e.g., Cassidy & Shaver, 1999; Goldberg, 2000; Grossmann, Grossmann & Waters, 2005; Sroufe, Egeland, Carlson & Collins, 2005a). John Bowlby regarded attachment as a biological instinct which evolves to ensure the survival of the vulnerable young (Bowlby, 1969). In light of the implications of attachment theory and research for practice, there remains a lack of research exploring interventions which encapsulate the principles of an attachment-based framework in the school context. The principle aim of this research was to address this gap in the literature by implementing an intervention designed to focus upon building the attachment between a group of five primary-aged pupils with identified insecure attachment styles, and a key adult figure in the school context. The intervention hoped to support the children to form a more positive sense of themselves and themselves in relation to others. The ten week intervention consisted of weekly one hour sessions based in a mixed, Church of England mainstream primary school within an outer London borough, in which the researcher worked as an Educational Psychologist. The research adopted a mixed methodology, with a predominant qualitative approach, with descriptive quantitative analysiS. The perceptions of children in relation to attachment concepts were explored both before and following the intervention using a semi-structured interview. The interviews were analysed using thematic analysis. Quantitative tools were also used, including behaviour rating scales completed by the children's class teachers, pre and post intervention. The findings revealed positive changes in the children's behaviours and experiences following the attachment intervention. These observations gave rise to theoretical and practical implications, foremost, that Internal Working Models can be positively shifted to some degree, and have an impact on the child's social and emotional behaviours. Practical implications focussed on the implementation for developing attachment-based interventions with adults in the school setting, in order to enhance their sensitivity to children's attachment needs and facilitate children's perceptions of the teacher and school context as a 'secure base'. Further implications of the research discussed areas such as pre-service training for teachers and partnerships with parents. Future avenues of research in relation to this study were explored. The research highlighted the essential role that adults in the school context can play in the lives of vulnerable children with insecure attachment difficulties.