HMRC says in its latest Agent Update that the new process has been operating since early summer. The aim is to identify potential overpayments and deal with refunds more quickly.

If HMRC thinks you may be due a refund, it will send you a letter showing details of your employment and National Insurance contributions. You will need to check that the information is correct and either confirm it or tell HMRC what needs changing.

You can respond online through GOV.UK or complete and return the form included with the letter. HMRC is specifically warning recipients not to ignore the correspondence, as it needs the information before it can complete its review and confirm whether a refund is due.

HMRC has also published an online service for National Insurance refund claims where a letter has been received. Once the information has been submitted, HMRC will check the position and write back with the outcome.

As with any unexpected tax refund correspondence, it is worth checking that the letter is genuine before providing information. HMRC says its refund notifications will never ask you to click on links. If in doubt, go directly to GOV.UK rather than following a link in an email or text.

Anyone receiving one of the new letters should therefore check the figures promptly. Even if you were unaware that you had overpaid National Insurance, HMRC may already have identified a potential refund from the information it holds.