We asked HMRC and DWP when they expect to have a firmer idea of the scale of the issue and the timeframe for making back payments. HMRC told us it intends to send out the letters to potentially affected people over the next 18 months. It added it expects to turn around 80% of responses within 15 working days, correcting the National Insurance record and notifying DWP.42 DWP told us it does not have a clear, formal delivery plan for completing back payments. The provision in DWP’s 2022–23 accounts 34 Qq 51,61 35 Q 52 36 Q 56 37 Qq 53, 54, 62 38 Qq 59–60; DWP ARA 2022–23, pages 293, 376 39 Qq 61, 63–64 40 Q 58; DWP ARA 22–23, pages 274, 293, 374 41 Qq 68–71 42 Qq 55, 65–67 The Department for Work & Pensions Annual Report and Accounts 2022–23 15 assumes a completion date in 2027–28, but DWP told us it hopes to do it quicker than this.43 It suggested that caseworkers with experience remediating previous State Pension underpayments have the right skillset to roll forward onto HRP, which may help speed the process.44