A cross-sectional telephone survey of 997 adults in England, Scotland, and Wales found that perceptions of the swine flu outbreak were linked to changes in behaviour. About 37.8% of participants reported performing recommended behaviours, such as increased handwashing and surface cleaning, within four days of the outbreak. Only 4.9% engaged in avoidance behaviours, such as avoiding crowds. Factors associated with recommended behaviour changes included the perception that swine flu was severe, that the risk of catching it was high, that the outbreak would last a long time, and that the authorities were trustworthy. Conversely, uncertainty about the outbreak and the belief that it had been exaggerated were linked to lower likelihood of change. Ethnic minority participants were more likely to adopt recommended behaviours, with an odds ratio of 3.2. The study highlights the importance of clear communication about the outbreak and the need to address public concerns about the severity and management of the disease. It also suggests that public health messages should focus on the effectiveness of recommended actions and the duration of the outbreak to improve compliance. The findings indicate that while the government's leaflet had limited impact on behaviour change, it was associated with lower anxiety. The study underscores the need for targeted communication strategies to improve public understanding and response to health threats.A cross-sectional telephone survey of 997 adults in England, Scotland, and Wales found that perceptions of the swine flu outbreak were linked to changes in behaviour. About 37.8% of participants reported performing recommended behaviours, such as increased handwashing and surface cleaning, within four days of the outbreak. Only 4.9% engaged in avoidance behaviours, such as avoiding crowds. Factors associated with recommended behaviour changes included the perception that swine flu was severe, that the risk of catching it was high, that the outbreak would last a long time, and that the authorities were trustworthy. Conversely, uncertainty about the outbreak and the belief that it had been exaggerated were linked to lower likelihood of change. Ethnic minority participants were more likely to adopt recommended behaviours, with an odds ratio of 3.2. The study highlights the importance of clear communication about the outbreak and the need to address public concerns about the severity and management of the disease. It also suggests that public health messages should focus on the effectiveness of recommended actions and the duration of the outbreak to improve compliance. The findings indicate that while the government's leaflet had limited impact on behaviour change, it was associated with lower anxiety. The study underscores the need for targeted communication strategies to improve public understanding and response to health threats.