Despite being labelled the “deadliest fraud in the history of human civilisation”,1 filter tips now feature on almost every mass-produced cigarette smoked across the globe.2 After filters first appeared in the 1860s as an attempt to protect against tobacco flakes entering the mouth,3 the tobacco industry introduced modern cellulose acetate cigarette filters in the 1950s to alleviate public concerns about smoking-related lung cancer.4 Filters and innovations to filters have been consistently marketed as a means to reduce smoking-related health risks,5 with the very name ‘filter’ suggesting reduced harm.6 For instance, filter perforations introduced in the 1970s and 1980s to create ‘light’ and ‘mild’ cigarettes produced lower machine-tested yields of tar and nicotine. When smoking, however, the perforations are blocked by smokers’ fingers,7 8 serving to increase rather than decrease harm as…