ABSTRACTThis paper explores selected findings from a qualitative study of the 1989 Children Act, which examined ways in which the new definitions of significant harm were being interpreted in practice. Significant harm is seen as a major site where state intervention and family autonomy are balanced, especially through establishing thresholds for intervention. The data are analysed in relation to the social work processes of assessment, intervention and evaluation. These are seen as a series of interactions between families and practitioners, in which goals are identified, methods used and resources mobilized. Key decisions and levels of change address the paramountry of the child's welfare. These processes are also under‐pinned by new legislative requirements. The practitioners displayed their professionalism during a period of transition and change. Social work processes facilitated non‐judgemental practices which empowered the families in the difficult circumstances of their lives. The paper concludes that balancing state intervention and family autonomy requires social work of a high order and a profound understanding of complex iss