The recent development of electronic logbooks with secure off‐device data storage provides a rich resource for research. We present the largest analysis of anaesthetic logbooks to date, with data from 494,235 cases logged by 964 anaesthetists over a 4‐year period. Our analysis describes and compares the annual case‐load and supervision levels of different grades of anaesthetists across the UK and Republic of Ireland. We calculated the number of cases undertaken per year by grade (median (IQR [range]) core trainees = 388 (252–512 [52–1204]); specialist trainees = 344 (228–480 [52–1144]); and consultants = 328 (204–500 [52–1316]). Overall, the proportion of cases undertaken with direct consultant supervision was 56.7% and 41.6% for core trainees and specialist trainees, respectively. The proportion of supervised cases reduced out‐of‐hours, for both core trainees (day 93.5%, evening 86.3%, night 78.6%) and specialist trainees (day 81.0%, evening 67.7%, night 56.4%).