Millions of UK households are likely to begin receiving tax letters from the HMRC between June and August. If you have overpaid Income Tax, you might be due a P800 letter in the post.

In addition to employees paid through PAYE, pensioners who have overpaid tax could also be affected. Overpayments can happen for a variety of reasons, with the most common being incorrect tax codes. For the current tax year, the standard tax code is 1257L, which typically applies to individuals with one job or pension. This allows you to earn £12,570 annually before income tax is applied, as it reflects your personal allowance.

However, not everyone will have this tax code. For example, if you have a second job, it might use a BR, D0, or D1 tax code. If your personal allowance doesn't apply, you could be assigned an 0T tax code.

To check your tax code, look at your most recent payslip. If you've left a job recently, check your P45.

You can also find it online through GOV.UK using your Government Gateway ID - a 12-digit number that's free to register and grants access to UK government services.

MoneySavingExpert has issued a warning about fraudsters posing as HMRC, urging people to be vigilant. They stress that HMRC will never text, email, or call regarding tax refunds-it will always communicate by post first.

If you are genuinely due a refund, HMRC might follow up with a text or prompt you to claim online, but only via an official GOV.UK website, and never through third-party links. Always check the URL carefully.

To make a claim, you will need, your P800 reference number and your National Insurance number

If you have been on the wrong tax code for a while, you can typically claim back up to four previous tax years. In certain cases-particularly if HMRC was at fault-they may issue refunds beyond that.

If an incorrect tax code led to underpayment, you will be responsible for settling the shortfall.