HMRC State Pension Error UK | How to Identify and Fix the Issue

There have been two major types of HMRC-related pension errors reported recently: one involving the online forecast tool and another regarding tax code mistakes for current retirees.

Depending on whether you are still working or already retired, here is how to identify and fix the issue.

1. The 2026 Forecast Tool Error (For those still working)

In February 2026, HMRC admitted that its “Check your State Pension” online tool had been providing incorrect estimates for nearly a decade.

• The Error: About 800,000 people received overestimated forecasts because the tool failed to account for “contracted out” years (periods where you paid into a private or workplace pension instead of the additional state pension).

• The Fix: * HMRC updated the tool on February 13, 2026.

  • If you checked your forecast before this date and reach state pension age after April 2029, you should re-check your forecast now via the Government Gateway.

  • If you now see a gap, you may need to make voluntary National Insurance (NI) contributions to top up your record.

2. Tax Code & Overpayment Errors (For current retirees)

If you are already receiving your pension and noticed a drop in your payments or received a “brown envelope” (P800 tax calculation), it is likely a tax code error.

• The Error: HMRC often applies an “emergency” tax code to the first withdrawal from a pension pot, or fails to update your record when you transition from full-time work to retirement.

• The Fix:

  • Contact HMRC: Call the Income Tax helpline at 0300 200 3300. Have your National Insurance number ready.

  • Claim a Refund: If you were overtaxed on a lump sum, you usually need to fill out a specific form (P55, P53Z, or P50Z) to get your money back within 30 days.

  • Extra-Statutory Concession A19: If HMRC delayed using information they already had, resulting in a tax bill for you, you can ask them to “write off” the arrears under ESC A19.

Also Read : Latest 2026 Seminar Topics For Computer Science

3. Underpaid State Pensions (Historical LEAP Exercise)

The Department for Work and Pensions (DWP) is also in the middle of a massive “Legal Entitlements Administrative Exercise” (LEAP) to correct historical underpayments, particularly for:

• Married women who reached state pension age before April 2016.

• Widows and those over 80 who were not moved to the correct higher rate automatically.

• Action: In most cases, the government will contact you automatically if you are owed money, but you can use the LCP State Pension Underpayment tool to see if you might be affected.

Summary Table: Who to Contact