Recognizing that robust information on health systems in other countries can provide valuable lessons for the English National Health Service, the Department of Health commissioned an academic team to provide an 'On-call Facility for International Healthcare Comparisons' in 2005. This paper describes the work of this novel approach to informing policy and reviews the experience of the first two years. It illustrates the well-documented challenges of comparative analysis of health systems. One important issue is understanding the health system context so as to interpret phenomena and draw appropriate policy conclusions. Other challenges include the potential tension between academic interest and rigour, and the need for timely analysis to inform the Department of Health's rapidly changing policy agenda. The diversity and nature of topics covered, as well as the rapid turn-around time have meant that the Facility has had to balance rigour and timeliness carefully to ensure the value and relevance of reports. A strong research base linked with an international network of country experts promotes the provision of high quality analyses at relatively low costs. However, such an arrangement can only be sustained if it provides scope for additional primary research. A formal evaluation of the influence on health care policy-making in England is not yet available. Such knowledge will be of crucial importance for the development of similar resources elsewhere.