UK Government IT failures which have led to millions receiving the wrong pension for decades are a sign the Department for Work and Pensions (DWP) is "broken beyond repair", the SNP has said.
MP Kirsty Blackman said it was "difficult to comprehend" how the major blunder had occurred.
It is thought the errors have been known about since the 1990s but have not been corrected.
Official analysis published last month suggests that 23% of pensioners were underpaid whilst 17% were overpaid.
Blackman, who is the SNP's Work and Pensions spokesperson, said only independence can protect Scotland's pensioners.
She said: "The scale of this mistake is difficult to comprehend.
"If the DWP was able to hide the fact they had been been paying millions of pensioners the wrong pension for decades, what else are they hiding?
"The DWP – and the wider Westminster system – is broken beyond repair. Only independence can protect Scotland's pensioners."
Sir Steve Webb, who served as pensions minister from 2010 to 2015, said he was never aware of the problem.
He said: “The scale of these errors is truly mind-blowing.
“Although the absolute size of the errors is typically small, the number of people potentially affected is huge. More worrying is the total lack of transparency.
“It beggars belief to hear that a government department could simply decide that it was acceptable to pay the wrong rate of pension for decades but feel under no duty to tell parliament or the public.
“If the Department for Work and Pensions has sat on this secret for decades, it makes you wonder how many other things simply get brushed under the carpet.”
The problem is linked to the Pension Strategy Computer System, and its inability to accurately uprate an element of the state pension called the graduated retirement benefit.
Some people have been both overpaid and underpaid in different years, with the vast majority of errors worth one or two pence per week.
In 2021, the National Audit Office found that problems with the system had separately led to 134,000 people who had claimed their state pension before April 2016 not receiving their full entitlement. The average underpayment was estimated at about £8900.
