The outbreak of Legionnaires' disease that occurred in Hereford, West Midlands UK in 2003 was the single largest outbreak of Legionnaires' in Hereford and one of the first to challenge the newly formed Health Protection Agency. This was, de facto a 'public health incident' requiring not only the investigation and management of a community outbreak of infectious disease, but also one that had to take into account other issues including: uncertainty regarding roles and responsibilities, political considerations and communication needs including sustained media attention. The incident also demonstrated the 'added value' of an integrated health protection response. The practical lessons learned from outbreaks are rarely described, particularly operational aspects. This paper summarises the outbreak, outlines specific elements of the response and identifies some of the key learning points for the new Agency and its partners. A number of these lessons have a generic applicability to the handling of public health incidents.