Official error occurs when a benefit is paid incorrectly due to action, delay or a mistake by the Department, a local authority or HM Revenue & Customs.18 In 2024–25, official error overpayments were estimated at £1.0 billion, up from £0.8 billion in 2023–24, and official error underpayments were estimated at £1.2 billion, up from £1.1 billion in 2023–24.19 Reducing these amounts is largely within the Department’s own control.