In last month's issue of the Public Health, Black et al. present evidence for a deepening disparity in childhood obesity between the most and least deprived children in the United Kingdom and called for research into why this might be. While the reasons are no doubt complex and multifactorial, available spaces for outdoor play in more deprived areas, and their attractiveness or otherwise, might be an important factor. Specifically, areas heavily contaminated with dog faeces can dissuade people, including children and other vulnerable individuals, from taking outdoor exercise.