There are a number of reasons why you might need to contact HMRC about changes in your income. 

HMRC’s guidance states that this could happen because you:

  • did not realise you needed to tell HMRC about it;
  • were not sure how to declare it; or
  • did not declare it because you could not pay the tax.

For example, reasons you may need to contact HMRC are if you are self-employed, a company director, have annual income over £100,000 and / or have undeclared income from savings, investment, property or overseas income. The £100,000 threshold for the Self-Assessment threshold for taxpayers taxed through PAYE only, has increased from £100,000 to £150,000 with effect from 6 April 2023. However, the Self-Assessment for 2022-23 tax returns remains at £100,000.  

Taxpayers that need to complete a Self-Assessment return for the first time should inform HMRC as soon as possible. The latest date that HMRC should be notified is by 5 October following the end of the tax year for which a Self-Assessment return needs to be filed. If you are required to submit a Self-Assessment return for 2022-23, you should ensure that you file your tax return electronically and pay any tax due by 31 January 2024.

HMRC has an online tool www.gov.uk/check-if-you-need-tax-return/ that can help you check if you are required to submit a Self-Assessment return.

There are two small exemptions from tax that may apply:

  • If you make up to £1,000 from self-employment, casual services (such as babysitting or gardening) or hiring personal equipment (such as power tools). This is known as the trading allowance.
  • If your annual gross property income is £1,000 or less, from one or more property businesses you will not have to tell HMRC or declare this income on a tax return. For example, from renting a driveway. This is known as the property allowance.

Where each respective allowance covers all the relevant income (before expenses) the income is tax-free and does not have to be declared.

If you have undeclared income, it is always preferable to contact HMRC as soon as possible. We would be happy to assist.