Martin Lewis has issued a clarion call for Britons to check they are being taxed correctly as “millions” are currently overpaying.

The financial journalist urged workers to check they are on the correct HMRC tax code as it’s on your head if you are paying the incorrect amount.

He told listeners on his BBC podcast: “You need to know your tax code and what it means, it’s your legal responsibility – it’s not your employer’s, not HMRC’s.

“Millions are wrong. Millions are overpaying. Millions are underpaying. It all causes a nightmare, make sure you know what your tax code is and check that it’s right.”

A person’s tax code can be found on their payslip and it indicates how much tax HMRC will deduct from their pay through the PAYE system.

The most common code is 1257L, which means a person pays income tax at the basic rate of 20 percent on their earnings above £12,570 a year.

A person’s tax code may change if their circumstances do, such as taking on a new job, and if your details are not up to date, you could be put on an emergency tax code, and pay the wrong amount of tax.

How do I check my tax code?

You can find your tax code on your payslip, your personal tax account or on the HMRC app.

If you believe you are on the wrong tax code, you can raise the issue with HMRC by calling the authority on 0300 200 3300.

The group can then change your tax code so you are taxed correctly, and you will be reimbursed any overpaid tax.

HMRC may also reach out to you if you are owed a tax rebate by sending you a P800 letter or a simple assessment letter.

The letter may also say that you can claim online – which can be done by logging into your personal tax account – or through the HMRC app.

It’s worth creating a personal tax account as well as it stores a lot of useful information about your tax record.

This includes your National Insurance contributions towards your state pension, and if you have any gaps in your record and how to fill these in.

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