BackgroundIn 2006, the Health Service Executive (HSE) in Ireland established an Expert Advisory Group (EAG) for Diabetes, to act as its main source of operational policy and strategic advice for this chronic condition. The process was heralded as the starting point for the development of formal chronic disease management programmes. Although recommendations were published in 2008, implementation did not proceed as expected. Our aim was to examine the development of recommendations by the EAG as an instrumental case study of the policy formulation process, in the context of a health system undergoing organisational and financial upheaval.MethodsThis study uses Kingdon’s Multiple Streams Theory to examine the evolution of the EAG recommendations. Semi-structured interviews were conducted with a purposive sample of 15 stakeholders from the advisory group. Interview data were supplemented with documentary analysis of published and unpublished documents. Thematic analysis was guided by the propositions of the Kingdon model.ResultsIn the problem stream, the prioritisation of diabetes within the policy arena was a gradual process resulting from an accumulation of evidence, international comparison, and experience. The policy stream was bolstered by group consensus rather than complete agreement on the best way to manage the condition. The EAG assumed the politics stream was also on course to converge with the other streams, as the group was established by the HSE, which had the remit for policy implementation. However, the politics stream did not converge due to waning support from health service management and changes to the organisational structure and financial capacity of the health system. These changes trumped the EAG process and the policy window remained closed, stalling implementation.ConclusionsOur results reflect the dynamic nature of the policy process and the importance of timing. The results highlight the limits of rational policy making in the face of organisational and fiscal upheaval. Diabetes care is coming on to the agenda again in Ireland under the National Clinical Care Programme. This may represent the opening of a new policy window for diabetes services, the challenge will be maintaining momentum and interest in the absence of dedicated resources.Electronic supplementary materialThe online version of this article (doi:10.1186/1478-4505-12-53) contains supplementary material, which is available to authorized users.