Author note (corresponding author, on behalf of all authors): We have identified several points in this version that will be corrected or clarified in a revised version, to be posted shortly:

Damages and legal costs. Some totals combine damages and legal costs without saying so. For example, the 2024/25 figure of £760m is total paid (damages plus NHS and claimant legal costs), of which £626m is damages. All totals will be labelled consistently, and the basis of each calculation stated. HRG figures. These are National Schedule of NHS Costs reference costs, not Payment Scheme tariff prices. The terminology will be corrected, and the explanation of the year-on-year change in planned caesarean unit costs revised. Labour attribution. Our eleven-code attribution (55.9% of obstetric damages) counts only labour-exclusive cause codes. Because NHS Resolution records a single primary cause per claim, intrapartum harm recorded under generic codes is excluded, so the figure is a lower bound. This will be stated explicitly, and we will add a sensitivity analysis. Any less conservative attribution increases rather than reduces the cost difference between planned vaginal birth and planned caesarean.