Ireland, like many countries, has reconfigured emergency care in recent years towards a more centralised model. Although centralisation is presented as ‘evidence-based’, the relevance of this evidence is challenged by groups which hold values beyond those implicit in the literature. The Study of the Impact of Reconfiguration on Emergency and Urgent Care Networks (SIREN) programme was funded to evaluate the development and performance of emergency and urgent care systems in Ireland. SIREN found that the drivers of reconfiguration in Ireland are based on safety and efficiency claims which are highly contestable. Reconfiguration was not associated with improvements in safety or efficiency and may have exacerbated the growing capacity challenges for acute hospitals. These findings are consistent with UK research. Our study adds to an emerging literature on the interaction between a narrow technocratic approach to health system planning and the perspectives of the public and patients.