Martin Lewis issues tax warning to anyone who took a summer job

The Money Saving Expert says anyone who did a summer job or a temp job needs to be alert

Martin Lewis has issued a tax warning to anyone who took a temp job or a summer job.

The Money Saving Expert site says that workers may well have ended up paying income tax they don’t actually owe.

In the current tax year (April 6, 2026 to April 5, 2027), most people can earn up to £12,570 without paying any income tax – this is your tax-free personal allowance.

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But sometimes, Martin says employers can either make a mistake or don’t process a staff member’s details on time, which means they can be put on a temporary emergency tax code instead and end up paying too much. These include 1257L W1, 1257L M1 or 1257L X.

The MSE website states: “With these emergency codes, tax is calculated just on that week’s or month’s pay in isolation, so you don’t get the full benefit of your yearly tax-free personal allowance. For example, if you stopped working after only a few weeks or months, you may have earned well below £12,570 but still been taxed – in which case you could be due a refund.”

It explains that it’s relatively easy to check and claim a refund however.

And it outlines clearly what workers need to do:

• If this was your only paid employment since 6 April 2026 and you won’t work again this tax year. If you’ve finished the job (and you won’t work again between now and 5 April 2027), you can claim a refund online. It may take a couple of weeks to get a reply, but the refund will then be paid directly into your bank account.
• If you’re still working, or you may work again this tax year. Here there are a couple of steps… You’ll get a new tax code to help you reclaim any overpaid tax. If you’re still working (or have/will start a different job this tax year), HMRC will update your tax code and your (new) employer will use that to automatically adjust your pay to refund any overpaid tax. Check your tax code & contact HM Revenue & Customs (HMRC) to correct it if wrong. You can find this on your payslips or through your Gov.uk personal tax account. If your tax code ends in W1, M1 or X, you are (or were) on an emergency code. If so, call HMRC on 0300 200 3300 to resolve it.

For more help with income tax, you can check the MSE free tax code calculator on the website here.