More than 100,000 people are believed to be affected - and could miss out on huge sums of cash

Sir Steve Webb said a HM Revenue & Customs (HMRC) campaign to track down more than 180,000 who have missed out on national insurance (NI) credits for time raising children is set to fail.

In an effort to track down those affected, mainly women, HMRC has issued hundreds of thousands of letters to those over the state pension age. If you think you could be affected, here's how to check your eligiblity

A historical error saw thousands of pensions missing out on money they shold have otherwise had made available to them

DWP has issued a warning to thousands of married women over State Pension back payments after the National Insurance contributions mix-up.

HMRC is trying to trace 180,000 pensioners who may have been underpaid.

The Department for Work and Pensions (DWP) estimates that £1billion will need to be paid out in arrears to rectify state pension underpayments.

Former Liberal Democrats pensions minister Sir Steve Webb says HMRC's errors may lead to tens of thousands of older people missing out on state pension cash.