This paper reports on the operation of the DCU Shaped Professional Learning Network (DCU SPLN), an initiative of the Centre for Evaluation Quality and Inspection (EQI) at Dublin City University. The DCU SPLN was initially established in Belfast, Northern Ireland as part of the Erasmus+ Project, 'Polycentric inspections of networks of schools', the focus of which was to provide an assessment of the potential of polycentric inspection as a tool for improving school effectiveness and outcomes. The cluster has now grown to 140 schools organised in regional clusters throughout Northern Ireland. The paper provides examples of the impact of the network on policy and practice in Northern Ireland. Firstly, it has a Hearts and Minds driving force that is centered on the ethical use of first-hand evidence to drive school improvement and associated action research. Secondly, it is underpinned by the existence and support from external agencies, in this case, researchers at EQI. Thirdly, the professional development provided to schools by EQI and subsequent adjustments by participants and advisors had a direct ongoing positive impact on improving the actual quality of learning in individual schools. Finally, one of the key learning points was the gradual transfer of responsibility for professional learning provision from the EQI researchers to the leaders and teachers involved in the cluster. The paper concludes with drawing some general conclusions about the role of networks in educational practice.