The cost to health services of treating cases involving clinical negligence specifically or cases of avoidable harm to patients is unknown. The Organisation for Economic Co-operation and Development estimates that treating cases where harm was avoidable costs developed countries 8.7% of their health expenditure each year, on which basis the costs in England could run to tens of billions.18 Both the Department and NHS Resolution told us the most important thing is therefore to prevent 10 Q 97 11 Qq 61, 64, 75, 85, 100 12 C&AG’s Report, paras 1.2, 1.4 13 Fit for the future: 10 year health plan for England, July 2025 14 Q 97 15 C&AG’s Report, Figure 1 16 Q 94 17 Billions to be redirected back into patient care with NHS reform - GOV.UK; and Letter from DHSC, dated 11 December 2025 18 C&AG’s Report, para 13 11 harm from happening to patients in the first place.19 NHS England told us it is making considerable efforts around patient safety and that there is no evidence that the levels of harm are increasing.20