Abstract
This research examined how a sample of English probation officers (POs) applied attachment theory as they supervised service users. Using an action research methodology over six months, the research identified aspects that were readily utilised (the idea that POs can sometimes represent a secure base figure and that attachment histories were significant). However, others offered little utility (the concept of mentalisation as a facility rooted in early attachment and the classification of attachment style). The reasons for this are explored and the process by which specialist research knowledge is applied by non-specialist practitioners is considered.