Another non-native species threatens to become naturalised in Britain, with the discovery of large numbers of North American Bullfrogs Rana catesbeiana at a site in East Sussex. This species has been widely introduced outside its natural range, and has been blamed for diminishing numbers of local amphibians and other wildlife. As it is a potentially damaging addition to our fauna, in this article we draw attention to the threat posed by this species, and outline measures being taken to attempt to eradicate the population.