Thesis Statement The novel contribution of this thesis is the application of Information Visualisation techniques to the analysis of databases of safety related incidents. It also includes an extended case study on the effect of Safety Culture on the development of technological systems intended to help safety. The large-scale deployment of automated systems has become commonplace. Accidents involving transportation, petro-chemical and nuclear systems have happened. Analysis of accidents and incidents is a commonly used method of gathering information about the safety of systems. Such information can also be used to prevent future failures. This thesis presents a novel application of the techniques of Information Visualisation to the analysis of railway incident data. Effective analysis of data about safety-critical systems requires a functioning safety culture within the organisation operating it. A fundamental theme throughout this thesis is that technological changes cannot be applied independently of the organisational context. An extensive case study is also made of the issues surrounding safety culture, with reference to the Ladbroke Grove and Hatfield accidents.