Research suggests that interprofessional working is key to child protection but it is also challenging since misunderstandings and omissions can easily occur. This article explores interprofessional working in referrals to supported child contact services in England. It aimed to understand why procedures and tools introduced to improve interprofessional working in this area failed to have the desired effect. The study adopted a systems approach and involved 58 hours of observations in six case study child contact centres covering both supervised services (which offer a high level of monitoring of contact) and supported services (which provide little oversight). In addition, 47 interviews were conducted with individuals working in centres and solicitor, social worker and judge referrers. The findings demonstrate that cases which could not be safely managed continued to be referred and accepted at supported child contact centres because all actors believed it was someone else's role to analyse the case and make a decision to accept or reject. Only social worker referrers took responsibility for this role but some social workers continued to refer cases that could not be safely facilitated because they assumed the service provided a higher level of vigilance then existed. The study draws attention to the limits of tools and protocols in enabling safe practice and the importance of exploring the potential for, what I term, 'systemic role contradictions'. Key practitioner messages • Tools and forms alone are unlikely to address problems in interprofessional working when the challenges are fundamentally at a cognitive level. • Actors in a system may experience, what I term, 'systemic role contradiction', whereby each assumes that the other is responsible for key aspects of a process because the task is inappropriate to their own expertise. • The complex, adaptive nature of child protection systems makes interprofessional working inherently unpredictable. • Actors construct their roles based on 'local rationalities', including understandings of their own and others' capacity and (mis)perceptions of services provided by other actors. These rationalities should be explored to identify problems.