HMRC warning to fix 'costly mistake' or face 'nasty unexpected bill in January'

A HMRC warning has been issued as taxpayers are urged to check their tax code on their pay slips - or risk a bill post- Christmas. BizSpace's expert team is highlighting the risk of coughing up too much to HMRC without realising it, or facing a nasty unexpected tax bill after Christmas.

The experts pointed out that the devil is in the detail – specifically, your tax code, easy to spot online or on your pay slip, P60, or P45. In most cases, HMRC will automatically update your tax code when your income changes. They’ll usually get this information from your employer.

If HMRC has the wrong information about your income, you may be given an incorrect tax code. To correct your tax code, make sure HMRC has up-to-date details about your income. They warned: "Keeping an eye on your tax code and understanding its implications is essential for managing your finances effectively.

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"Mistakes can happen, but by staying proactive and informed, you can catch errors early, avoid unexpected bills, and ensure you’re not paying more than you should." If you think your tax code is wrong, you can use the Check your Income Tax online service to update your employment details or tell HMRC about a change in income that may have affected your tax code.

For example, you can add company benefits or add missing employers or income or claim employment expenses or update your estimated taxable income. HMRC may change your tax code as a result of the updates you make in the online service, it says.

If you think your tax code is wrong and you cannot use the online service, you can contact HMRC. HMRC will tell you if they change your tax code. They will also tell your employer or pension provider that your tax code has changed.

Your next payslip should show your new tax code and adjustments to your pay if you were paying the wrong amount of tax.