Thousands of women could have been underpaid the state pension as far back as 1985, it has been reported.
Details of the lost cash has been uncovered in a new report which shows that one person was underpaid by a whopping £128,000.
In fact, an estimated 134,000 pensioners could be impacted with over £1billion owed between them.
It comes following errors at the Department for Work and Pensions (DWP), the National Audit Office (NAO) found.
The report investigated the problems and published an insight into underpayments with retirees losing an average of £8,900.
Those impacted are Brits who first claimed the state pension before April 2016 and didn’t have a full National Insurance record.
Most of those affected by the underpayments are women, the NAO discovered.
They should have received increases, but didn’t in an effort the NAO blamed on complex rules and outdated IT systems.
The DWP has started correcting the error with some pensioners already paid back thousands of pounds.
Some who have since passed away and their families may never receive what they owed, the NAO says.
Around 94,000 of those who were unpaid are still alive and an estimated 40,000 have died.
Head of the NAO, Gareth Davies said: “The impact of the underpayment of State Pension on those pensioners affected is significant.
“It is vital that the DWP corrects past underpayments and implements changes to prevent similar problems in future.”
The report says the exact amount and people affected isn’t certain, but the errors will be known once a review is completed.
According to DWP, it is working through identifying those affected and expects to have paid back the money by the end of 2023.
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A DWP spokesperson said: “We are fully committed to ensuring the historical errors that have been made by successive Governments are corrected, and as this report acknowledges, we’re dedicating significant resource to doing so.
“Anyone impacted will be contacted by us to ensure they receive all that they are owed.
“Since we became aware of this issue, we have introduced new quality control processes and improved training to help ensure this does not happen again.”
If you are owed money, you will have to wait for the DWP to send you a letter confirming your payment.