Capturing data about rare, hazardous events in perioperative care is challenging. The United Kingdom’s National Audit Project (NAP) programme, commissioned by the Royal College of Anaesthetists, endeavours to provide practical information for clinicians by systematically examining a large series of such events.1 Each NAP has focused on a different topic, and most recently the Sixth National Audit Project, ‘NAP6’, investigated life-threatening perioperative allergic reactions. A review of the methodology and findings of previous NAPs has previously been published in this journal.