The data on fraud, error and unfulfilled eligibility in the benefit system revealed that State Pension overpayments in 2023-2024 stood at £170m.

But that was significantly lower than State Pension underpayments which stood at £470m for the period.

The data estimated how much extra money benefit claimants could get if DWP had accurate information about their circumstances.

The unfulfilled eligibility rate for pension credit was 1.5%, which equates to £80m and compares to 1.1% or £50m in 2023.

Claimants failing to inform the DWP about reductions in financial assets was the largest issue.

Helen Morrissey, head of retirement analysis at Hargreaves Lansdown said: “We tend to assume benefits such as state pension will be paid out automatically at the correct rate, but we’re wrong. A lot of people aren’t receiving the money they are entitled too and for many it’s caused them to struggle financially.”

She warned that the key reason behind errors in state pension payments are inaccuracies around national insurance records.

Ms Morrissey said: “There have been high profile cases of groups who have not received the uplifts they were entitled to under the basic state pension system when their partners died for instance.”

When it comes to pension credit, there was unfulfilled eligibility of an estimated £80m.

Ms Morrissey said: “Much is made of the number of people who aren’t claiming pension credit when they should be, but we also need to look at whether those who do receive it are getting the correct amount.”