Thousands of pensioners could be owed £9,500 following an error by the Department for Work and Pensions (DWP).
The issue is linked to married and or widowed people, and those over the age of 80, who wrongly didn’t have their state pension automatically topped up.
If you reached the state pension age before April 6, 2016, you will be claiming the old basic state pension, which is worth up to £141.85 a week.