Universal Credit claimants could be left to wait until April 2024 for the government to fix a faulty operative system.
The Department for Work and Pensions (DWP) was found to only be correcting state pension records when they reach the eligible age.
The situation of lost national insurance credits could see people getting less state pension when they retire or wasting money on purchasing unnecessary top ups.
The issue came to light at the beginning of February when Lib Dem MP Wendy Chamberlain asked for answers in Parliament and a response from employment minister Guy Opperman confirmed the flaw.
Mr Opperman’s letter said that the automated process to add Universal Credit claimants’ data to their state pension records was suspended in 2017/18 and that corrections would not be completed until April 2024.
“The vast majority of people affected are many years away from reaching state pension age and will not be impacted by this issue when they make a state pension claim,” the letter added.
“For those who do need to claim their state pension, HMRC and DWP have implemented a manual process to correct NI records and state pensions.
“For those already claiming their state pension, who are affected by this issue, their state pension will be re-assessed and any underpayment issued accordingly as part of normal processes.”
Over the course of the investigation, which was completed by This is Money, it was claimed the issue was “internally well-known”.
The financial website said it contacted the DWP multiple times with cases of missed National Insurance credits while the Gov.uk website still claims Universal Credit claimants have their National Insurance credits updated automatically.
This is Money found ten examples of where cases have been missed.
A DWP spokesperson: “All of the cases raised have now been resolved and we are sorry for any inconvenience caused.
“We are working with HMRC on an improved process to add historic and future Universal Credit National Insurance credits to National Insurance records.”
The Independent has contacted DWP for further comment
