Overview
- HMRC data published in February found about 730,000 refunds went unclaimed last year, leaving £624 million with an average of £855 each.
- Refunds are no longer paid automatically, so people should review their P800 tax calculation letter and confirm details before claiming.
- The fastest route is the HMRC app or personal tax account, with online repayments usually in five working days and cheques taking up to six weeks.
- Pensioners are often hit by wrong state pension figures in tax codes, and other common causes include outdated codes, payroll mistakes, and part‑year work.
- Employers cannot file P800 claims for staff, and any overpaid tax must be reclaimed within four years of the end of the tax year.