Some 200,000 women could be owed thousands of pounds on their state pension, Martin Lewis believes.
MyLondon reports how the money-saving expert revealed his latest tip on his popular ITV show last night.
He said that women affected could be owed an average of £13,500 back on their state pensions after being underpaid.
Lewis told viewers: "This is for married women and widows who may have been underpaid aged 67 or over whose basic state pension was less than 60 per cent of their husband's.
"What has happened is the Department for Work and Pensions has said it is going to automatically refund and backdate. It will contact within the next few months those who should have got it but a computer glitch meant they did not, and this is a lot.
"Husbands 65 on or after the 17 March 2008 and you are on the 60 per cent? That's you.
"No uplift when your husband died and you should have got one? They will be automatically getting in touch with you, and some other categories.
"Some people, though, will still need to claim. If your husband turned 65 before March 2008 and you are being paid less than 60 per cent of the basic state pension, you will need to contact them.
"If you got divorced after retirement and your pension was less than your ex-husband's, you will need to contact them.
"I know, it's complex. There are free guides and tools online and then you call the pension service to check."
