HMRC sending brown envelopes to 210,000 people over state pension miscalculations

If you receive a brown envelope in the post over the next few weeks, it could be informing you that you're owed over £35,000 by HMRC. Thousands of people, mainly women, are being contacted by HM Revenue and Customs (HMRC) about money they're due because of a significant state pension error.

The problem predominantly affects women in their 60s and 70s who claimed Child Benefit between 1978 and 2000. Their National Insurance credits - which contribute to your state pension entitlement if you're not working - were not correctly transferred.

These National Insurance credits were known as Home Responsibilities Protection (HRP) until 2010. HRP reduced the number of qualifying years needed for parents and carers to claim the state pension.

It was mostly claimed by stay-at-home mums or anyone who took a break from paid work to care for a child or a person with a long-term disability or illness.

However, if someone claimed Child Benefit and didn't include their National Insurance number on the form, their HRP credits may not have been correctly transferred to their National Insurance record. As a result, this could have affected the amount of state pension they're receiving, according to the Mirror, reports the Manchester Evening News.

It's estimated that 210,000 people may have been impacted. Of this figure, 60,000 are now deceased - and their families can make a claim for any money owed.

People of retirement age are being prioritised to receive contact, as per ministerial assurances that the majority impacted by the error will have been addressed by April of the upcoming year. The usual payout is around £5,000, although in certain cases this can escalate into figures of tens of thousands of pounds.

One woman relayed her experience to Martin Lewis, founder of MoneySavingExpert.com, sharing how she was able to reclaim a staggering sum of £82,000.

A representative from DWP claimed, "The action we are taking now will correct historical underpayments made by successive governments. We are fully committed to addressing these errors, not identified under previous governments, as quickly as possible. We have set up a dedicated team and devoted significant resources towards completing this."

Unsure whether you've been underpaid on your pension?

The primary criterion for qualifying for a year of Home Responsibilities Protection (HRP) from 1978 include:.

- You must be receiving child benefit in your name (not a spouse or partner's).

- Your child should be under the age of 16 for the entire fiscal year in question.

- You were not making payments to a married woman's "reduced stamp".

If you believe you're coming up short, you are advised to review your state pension and your National Insurance record. For those who have reached pension age after April 5, 2010, any year of HRP/credits should appear as a complete year on your NI record.

If it doesn't, you may need to make further enquiries.

If you reached pension age on or before April 5, 2010, HRP was recorded differently and you'll need to contact the NI helpline to check if there is HRP on your record. The Government has also launched an online checker tool on Gov.uk to help you determine if you're likely eligible to make a claim.

To claim any missing HRP up until March 2010, you'll need to complete the form CF411.