The Munro Reviewhighlighted obstacles hindering the realisation of an ‘effective’ and ‘child-centred’ English child protection system, including the ‘risk’ associated with the social worker’s discretionary space. The review called for reform to enable practicing social workers to exercise their discretion in the best interests of the individual child. This article reports on the results of an iterative qualitative mixed-methods case study of one local authority child protection team, utilising focus group, questionnaire, interview, observation, documentary analysis and critical realist grounded theory, to explore whether, on encountering a discretionary space, social workers were willing to employ discretion, and the factors influencing this decision. The main findings included that social workers were experiencing discretionary space in an entrepreneurial, de jure and de facto sense and that practitioners were more likely to choose to exercise their discretion within the managerially sanctioned discretionary space. Whilst the research does offer some evidence in favour of Munro’s image for discretion within the system, it also suggests that further efforts may be required to better imbed ‘sanctioned’ discretionary space into local policy and procedures so that child protection social workers can more consistently employ their discretion in the interests of the individual child.