Claimants not reporting changes in their circumstances remains a key cause of people not receiving the full amount of benefit they are entitled to. Unfulfilled eligibility occurs where a claimant fails to provide accurate information or evidence to the Department about their circumstances and as a result does not receive their full benefit entitlement. Unfulfilled eligibility was estimated to be £3.7 billion in 2024–25, up from £3.1 billion in 2023–24. It particularly affects claimants of disability benefits, such as Personal Independence Payment, who fail to report that their condition has worsened. The Department acknowledges that building trust with customers is key to reducing the number of incorrect benefit payments, alongside making it easier for people to report changes of circumstances. It is launching a communications campaign in January 2026 to help customers identify what they need to tell the Department 5 and to encourage them to do so. The Department also acknowledges that it needs to do more to build public trust by ensuring that people feel raising concerns about potential fraud is worthwhile, and has agreed to consider what information it might be able to share about the outcome of cases with people who make fraud referrals. recommendation a. The Department should evaluate the impact of its communications campaign to encourage claimants to report changes of circumstances and publish the results by the end of 2026. b. In its Treasury Minute response to this report the Department should update us on how it plans to provide more information to update people who raise concerns with it about cases of potential fraud.