The United Kingdom was assessed as a low risk country throughout the 2003 global SARS outbreaks. Despite this, 368 reports of potential SARS cases were made to the Health Protection Agency (HPA) between March and July 2003. The public health actions undertaken in response to these reports, the establishment of reporting mechanisms and the development of guidance documents were substantial. Lessons learned from mounting a UK response to SARS included: the importance of international collaboration; formation of a UK-wide, multidisciplinary Task Force; flexible case reporting mechanisms; integration of surveillance and laboratory data; generation of prompt and web-accessible guidance and advice; availability of surge capacity; and contingency planning. Lessons learned are being incorporated into the HPA's preparedness to prevent and control future newly emerging infectious disease threats.