HMRC has repaid £56.9m in overpaid tax to people who accessed their pension for the first time between April and June this year. If you think that is a massive number, then may be shocked to hear the figure hits an estimated £1.3bn overall.

So why is this? This is an unintended consequence of the Pension Freedom and Choice reforms that came in 2015 and gave people greater flexibility on how they access their pension.

When people make the first withdrawal from their pension, they can be put on an emergency tax code whereby HMRC treats it as though that first payment will be repeated every month. This means that if you have taken out a sizeable sum, you could find yourself with a surprise tax bill.

It's shocking to think that this is still happening more than nine years after this reform came in. Many of these people will quite rightly not have anticipated something like this happening and will have had a nasty shock when their tax bill was much higher than expected.

This can cause huge problems — a tax nightmare is not the way to start your retirement.

Read more: How much do you need to save for retirement?

Of course, you can get a refund — either by waiting until the end of the tax year or filling in one of a number of online forms. There are known as the P55, P53Z or P50Z and you need to fill out a different one depending on your circumstances.

• A P55 should be used if you haven’t withdrawn your entire pension and are not taking regular payments.

• A P53Z can be filled out of you have withdrawn all your pensions and also receive other taxable income.

• A P50Z is for when you have withdrawn all your pension but you have no other taxable income.

The latest data shows HMRC processed more than 16,000 of these forms in the period between 1 April and the end of June, with the overwhelming majority of people completing the P55. You can either submit the form online or else print it out and post it to HMRC.

It’s a relatively straightforward process that should see your refund hit your bank account in a few weeks. However, it is a complication many people do not need and it’s a situation that should have been resolved years ago.

If you do get caught out, be sure to take swift action by filling out a form and getting your money back as soon as possible.

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