There are approximately six million of us in the UK who are due to receive refunds to an average of £400, and some reaching the £1,000s. This finding follows the annual check of who paid what, which also uncovered the one million people who have not paid the right amount of tax, owing an average of £600.

This is not the first time these inconsistencies have been uncovered. It follows the introduction of a new computer system at the HM Revenue and Customs, which is tracking down reconciled cases dating back many years. The good news is that anyone owed money will be paid back with interest without the need to contact them (although they do not give a timeframe for this!).

As the first letters start to find homes across Britain, here are some valuable need-to-knows:

• WHAT IS A TAX CODE?
  • These are a series of digits which tell your employers how much tax to deduct. One of the most common is the 747L code. Add a five to the end of the numbers (£7,475) and you’re presented with the amount you can earn before income tax is taken.

• THE WRONG POSTAL ADDRESS MEANS YOU WILL MISS THE REBATE
  • The HMRC must have the correct address for you in order to post out your tax rebate. If you’ve moved, or assume that your employer updates the address, think again. Update your address here: HMRC address update form

The government encourages you to save for your retirement by giving you tax relief on pension contributions. New regulations brought out earlier this year will allow everyone to contribute up to £50,000 per year and receive full tax relief at up to 50%. That includes high earners.

For those earning less than the £130,000 threshold, a financial contribution under the outgoing rules of up to £255,000 may be possible. To ensure that the Pension Input Period (PIP) allows this, careful consideration will be required.

The report outlined some key changes to be aware of: