MORE than £1 billion in state pensions have gone underpaid due to repeated human errors, Whitehall’s spending watchdog revealed today.

The National Audit Office said complex rules, a lack of staff training and outdated IT systems have led to the Department for Work and Pensions (DWP) short-changing 134,000 pensioners. 

Most are likely to be women, the watchdog said, but the true scale of the problem — affecting those who first made a claim before April 2016 — will only emerge once ministers have reviewed all cases and traced affected individuals. 

Those underpaid will receive an average of £8,900 each, the government confirmed, with a whopping £568 million going to widows and widowers who should have inherited more state pension entitlement from their deceased partner.

Public accounts committee chairwoman Meg Hillier said: “This is not the first widespread error we have seen. Correcting these errors comes at great cost to the taxpayer.

“DWP must provide urgent redress to those affected and take real action to prevent similar errors in future.”

A government spokesperson said ministers were tracing those affected while introducing new quality control processes to protect pensioners.