John O'Neill, a molecular biologist in Frank Herbert's 1982 novel ‘The White Plague’,1 seeks retributive justice for the death of his wife in a terrorist bomb blast by infecting those he holds responsible with an engineered pathogen that kills only women. The eponymous plague soon spreads uncontrollably with predictable catastrophic global consequences.

When the definitive history of armed conflict is written, the chapter on biological weapons will make for a long and disagreeable read. Now, happily, disavowed by most nations under the 1972 Biological Weapons Convention, the presumption is that any future deployment would be at the hands of rogue states, criminal gangs or perhaps terrorist organisations, to whom they could appeal because of their apparent ease of preparation and dissemination coupled with their sinister reputation and potential for causing mass casualties.

But Herbert's villain is different. He is a trained scientist possessing expert skills and with access to pathogens, reagents and cutting-edge technology. Such a person might appear outwardly to be part of the conventional academic establishment except that their motives impel them to act covertly outside the accepted ethical and legal boundaries of their profession. Such ‘outsiders’ evade detection because they act alone and can, through their privileged position, anticipate and thwart regulation or investigation. But is this frightening scenario more than just a plot for apocalyptic novels? Is it a credible threat?

In reality, such occurrences seem to be rare. In a comprehensive analysis of 180 incidents involving the use of biological agents during the last century, for instance, Carus2 noted that none of the confirmed bioterrorist attacks by non-state actors …