TL;DR: The Department for Work and Pensions has been correcting historic State Pension underpayments since 2020 under a programme known as LEAP (Legal Entitlements and Administrative Practices). The errors mainly affected married women, widows, and people over 80 entitled to Category BL or Category D pensions under the old basic State Pension rules. The National Audit Office reported that around 134,000 pensioners had been underpaid by an estimated 1.5 billion pounds in total, with the correction programme running through to 2027. A separate exercise corrects gaps in National Insurance records caused by missing Home Responsibilities Protection credits for parents (mainly women) between 1978 and 2010. Affected pensioners can check their position via the personal tax account on GOV.UK or by writing to the DWP, and may also be entitled to arrears running back several years.
Last reviewed May 2026
State Pension underpayments have become one of the largest welfare-correction exercises ever undertaken by the UK government. The errors mainly affect older women whose State Pension was calculated under the old basic State Pension rules in force before 6 April 2016, but they have also caught widows, divorced pensioners, and some pensioners aged 80 or over.
This guide sets out exactly what went wrong, which groups are affected, the correction programmes the DWP and HMRC are running, how to check whether an individual pensioner has been underpaid, and what to do if a payment error is suspected.
What the State Pension errors are and who is affected
The main category of error involves married women and widows who were entitled to claim a higher Category BL pension based on their husband's National Insurance record, but whose own pension was instead calculated only on their own (often shorter) NI record. Under the old basic State Pension rules a married woman could claim a "60 percent" Category BL pension based on her husband's record once both had reached State Pension age, and this often produced a higher amount than her own Category A pension.
For decades the DWP's processing was supposed to identify these cases automatically and adjust the pension. In practice some cases were never picked up, particularly where the husband reached State Pension age before computerised records were complete or where manual adjustment was required. Some women's pensions were paid at the low Category A rate for years longer than they should have been.
The second category involves widows whose pension entitlement should have been increased when their husband died, taking the higher of their own and the deceased's basic pension. Some widows continued to be paid at their own (lower) rate.
The third category involves pensioners aged 80 or over who were entitled to a Category D non-contributory pension if their existing pension was below the Category D rate. Some over-80s pensioners were not flagged for the Category D top-up and were therefore underpaid from age 80 onwards.
The fourth category is the Home Responsibilities Protection (HRP) issue: parents (mainly women) who claimed child benefit between 1978 and 2010 should have received NI credits under HRP to fill years out of paid work. Some parents' child benefit records did not properly trigger the HRP credit, leaving gaps in their NI record that reduced their State Pension. This is being corrected through a joint exercise by HMRC and DWP.
The LEAP correction programme
The DWP launched the Legal Entitlements and Administrative Practices (LEAP) correction exercise in 2020 after the issues were identified by Steve Webb (a former pensions minister) and the consumer journalist team at the time. The programme aims to identify all affected cases, recalculate the correct State Pension entitlement, pay the arrears, and uplift the future weekly pension to the correct level.
The National Audit Office reported in September 2021 that the DWP estimated some 134,000 pensioners had been underpaid by a total of around 1.5 billion pounds. The total has been revised upward as more cases have been identified. Some pensioners have received very substantial lump sums of arrears running into tens of thousands of pounds, plus ongoing uplift to their weekly pension.
The programme is being run in stages, focusing first on living pensioners and then on cases where the pensioner has died (in which case arrears are paid to the estate). The DWP has confirmed the exercise is expected to continue through 2027. Pensioners do not need to claim under LEAP themselves; the DWP is identifying cases proactively.
Affected pensioners are written to by the DWP when their case is reviewed. The letter explains the recalculation, sets out the arrears amount, and confirms the new weekly rate. The arrears are paid as a lump sum into the pensioner's bank account, and the ongoing weekly pension is uplifted to the new rate from a specified date.
The Home Responsibilities Protection (HRP) correction exercise
HRP was the predecessor to today's NI credits for parents and carers. Parents who claimed child benefit for a child under 16 between 6 April 1978 and 5 April 2010 should have had each year of HRP recorded against their NI record, reducing the number of qualifying years needed for a full basic State Pension.
The issue identified in 2022 to 2023 was that for some parents the HRP credit did not transfer correctly from the child benefit system to the NI record. The gaps in the NI record then reduced the State Pension. The number of affected cases is estimated by HMRC at hundreds of thousands.
HMRC began writing to potentially affected pensioners from autumn 2023, asking them to check their child benefit history and apply to have the missing HRP credits added. The application is made through GOV.UK using form CF411 or CF411A. HMRC then notifies the DWP, which recalculates the State Pension and pays any arrears.
This is a longer-running exercise than LEAP and is expected to continue for several years. Affected parents who do not receive a letter can still apply proactively if they believe they had child benefit claims between 1978 and 2010 that were not credited.
How to check whether you have been underpaid
The first practical step is to look at the State Pension paid each four weeks against the full basic State Pension rate or the full new State Pension rate for the appropriate year. For 2025-26 the full basic State Pension is 176.45 pounds a week and the full new State Pension is 230.25 pounds a week. A pensioner receiving substantially less than the appropriate full rate may have an incomplete NI record or be entitled to a Category BL or Category D top-up.
The second step is to obtain a current State Pension forecast from GOV.UK by logging into the personal tax account. The forecast shows the current entitlement, the maximum reachable, and any gaps. A forecast that shows fewer qualifying years than the pensioner believes they should have had is a flag for the HRP correction exercise.
The third step is to write to the DWP State Pension service requesting a review of the calculation. The letter should set out the marital history (date of marriage, spouse's name and NI number if known, date of any divorce or bereavement), the child benefit history (years of claim, child's names and dates of birth), and the reason for believing the pension may be wrong. The DWP responds in writing.
The fourth step, for HRP cases specifically, is to complete form CF411 (for HRP claims for years before April 2010) or CF411A (for the simpler online process introduced in 2023). HMRC processes the application and feeds the credits through to the NI record.
Arrears, time limits, and tax position
Arrears under the LEAP programme are paid in full back to the date the underpayment started. The DWP does not apply the standard 12-month time limit that applies to most retrospective benefit corrections, on the basis that the underpayment was caused by an official error and the pensioner could not have known to claim sooner.
State Pension arrears are taxable in the tax year they are paid (unless specifically allocated to earlier years by HMRC). A large lump sum of arrears can push the pensioner's total taxable income for the year into a higher tax band. HMRC's "spreading" treatment can apply to certain large arrears payments, allocating them to the tax years they relate to rather than the year of receipt, which can reduce the overall tax bill. The DWP and HMRC handle this between them in most cases; the pensioner does not need to claim it.
Arrears are not treated as capital for means-tested benefits for the year of receipt, and any income from them is disregarded for that year. After the disregard period the standard means-tested rules apply. Pensioners in receipt of Pension Credit or Council Tax Reduction should expect the DWP to handle the recalculation automatically.
If a deceased relative was underpaid
Where the pensioner has died, the DWP pays the arrears to the estate. This is part of the LEAP programme and the executor or administrator can apply on the deceased's behalf if the DWP has not yet identified the case. The application is made through the DWP State Pension service with the death certificate, grant of probate or letters of administration, and details of the marriage history.
Arrears paid to an estate are taxable income of the estate and may be subject to income tax if the estate's taxable income exceeds the trust and estate rates. Inheritance tax position depends on whether the arrears are received before the inheritance tax return is finalised; in most cases the arrears form part of the deceased's estate for inheritance tax purposes.
The same principle applies to the HRP correction exercise: if a deceased relative had been underpaid because of missing HRP credits, the estate can apply to have the credits added retrospectively and to receive any resulting arrears.
How we verified this
The information in this article is drawn from the National Audit Office's September 2021 report on State Pension underpayments, the Department for Work and Pensions' published updates on the LEAP programme, HMRC's published guidance on Home Responsibilities Protection corrections, and the Public Accounts Committee evidence sessions on the underpayment issue. The basic and new State Pension rates quoted are the statutory rates for 2025-26. No invented case numbers or pensioner details have been used. The official DWP and HMRC channels for contacting them are described as they currently operate.
Disclaimer: This article is general information about UK State Pension underpayments and the LEAP and HRP correction exercises. It is not personal advice. Eligibility for any correction depends on the individual's specific NI record, marital history, and child benefit history. Anyone who believes their State Pension may have been underpaid should contact the DWP State Pension service or HMRC directly and obtain a written response based on their personal records.
Frequently asked questions
What are the State Pension payment errors?
The main errors involve married women, widows, divorced pensioners, and those over 80 who were entitled to higher Category BL or Category D pensions under the old basic State Pension rules but whose entitlement was not correctly applied. A separate issue involves parents (mainly women) whose Home Responsibilities Protection credits did not transfer correctly from the child benefit system to the NI record between 1978 and 2010. Both groups are being corrected through DWP and HMRC programmes.
How do I check if I have been underpaid?
Compare your current State Pension to the full basic State Pension rate (176.45 pounds a week for 2025-26) or the full new State Pension rate (230.25 pounds a week). Obtain a State Pension forecast from GOV.UK to see your NI record. Write to the DWP State Pension service or HMRC for a review if you believe there is a discrepancy, providing details of your marital history and child benefit history.
How much could the arrears be worth?
It varies enormously by case. Some affected pensioners have received arrears running into tens of thousands of pounds, particularly where they were underpaid for many years. Others have received smaller amounts of a few hundred pounds. The arrears are paid as a lump sum and the ongoing weekly pension is uplifted to the correct rate from the date of correction.
Do I have to claim or will DWP find me automatically?
The DWP is identifying affected pensioners proactively under the LEAP programme and writing to them when their case is reviewed. The HRP correction is partly proactive (HMRC writing to potentially affected parents) and partly application-based (parents can apply themselves using form CF411 or CF411A). If you believe you may be affected and have not been contacted, you can write to the DWP or HMRC to request a review.
Are the arrears taxable?
State Pension arrears are taxable in the tax year they are paid, although HMRC's "spreading" treatment can allocate large arrears payments to the tax years they relate to instead, which can reduce the overall tax bill. The DWP and HMRC normally handle this between them. The arrears do not affect means-tested benefits for the year of receipt under the standard disregard rules.
