BACKGROUND: Most projections of climate change suggest an increased frequency of heatwaves in England over coming decades; older people are at particular risk. This could result in substantial mortality and morbidity. OBJECTIVE: To determine elderly people's knowledge and perceptions of heat-related risks to health, and of protective behaviours. METHODS: Semi-structured interviews: 73 men and women, 72-94 years, living in their own homes in London and Norwich, UK. RESULTS: Few respondents considered themselves either old or at risk from the effects of heat, even though many had some form of relevant chronic illness; they did recognize that some medical conditions might increase risks in others. Most reported that they had taken appropriate steps to reduce the effects of heat. Some respondents considered it appropriate for the government to take responsibility for protecting vulnerable people, but many thought state intervention was unnecessary, intrusive and unlikely to be effective. Respondents were more positive about the value of appropriately disseminated advice and solutions by communities themselves. CONCLUSION: The Heatwave Plan should consider giving greater emphasis to a population-based information strategy, using innovative information dissemination methods to increase awareness of vulnerability to heat among the elderly and to ensure clarity about behaviour modification measures.