HM Revenue & Customs (HMRC) has issued a fresh warning urging Brits to verify whether they need to file a Self Assessment tax return, highlighting that many may be unaware of the eligibility rules. In a post on X on Sunday, June 14, 2026, the UK tax authority asked: 'Unsure if you might need to complete a tax return?' It added that 'you may need to' if you are newly self-employed, a landlord, a new partner in a business partnership, or have earned over £1,000 (gross) through a side hustle.
Who Needs to File a Tax Return?
The UK Government website spells out the trigger points for having to file a return for the last tax year (April 6 to April 5) in more detail. This includes if any of the following applied: you were self-employed as a 'sole trader' and earned more than £1,000 (before taking off anything you can claim tax relief on); you were a partner in a business partnership; you had to pay Capital Gains Tax when you sold or 'disposed of' something that grew in value; you had to pay the High Income Child Benefit Charge and do not pay it through PAYE; or you are an off-payroll worker who is repaying a student or postgraduate loan.
A tax return may also be required if you have any untaxed income, for example: income from savings, investments and dividends; money from renting out a property; foreign income; or tips and commission.
Key Deadlines and Penalties
Self Assessment tax return is the system HMRC uses to collect Income Tax. In most cases, tax will be deducted automatically from wages and pensions. 'If you need to send a Self Assessment tax return, fill it in after the end of the tax year (5 April) it applies to,' the GOV.UK website explains. 'You must send a return if HMRC asks you to.'
'HMRC must be informed by October 5 if you need to complete a tax return for the previous year and you have either: not submitted a tax return before; registered before but didn't need to send a tax return for the tax year 2024 to 2025. You could be fined if you do not tell HMRC by 5 October.'
HMRC will work out how much you owe them based on what you report in the return. The bill is then due by January 31.
How to Check Your Status
The UK tax authority called on people to use their free online tool to check whether they need to be filing. The tool is available on the GOV.UK website and helps determine if you have any untaxed income or other triggers that require a return.
