Within a historically-informed framework utilising the related concepts of capability and intentions we identify and critically assess three core assumptions underlying the concept of food defence:1 that there is a 'real and current' threat to the food supply chain by terrorist organisations 2 such an attack is easy to do 3 the effects of such an attack can be extrapolated from food safety incidents.In doing so, we find that food defence is largely driven by perceptions of vulnerability, the effect of which is a misperception in threat.