HMRC Issues Urgent Self Assessment Reminder Ahead of October Deadline

As of the first quarter of 2025, around 4.4 million people in the UK were self-employed, representing approximately 13.5% of the workforce, according to Statista. For many who have recently set up their own business or started freelancing, the rules around tax can feel daunting, particularly when it comes to keeping on top of deadlines.

HM Revenue and Customs (HMRC) has now issued a UK-wide alert reminding taxpayers of a key date in the Self Assessment calendar. Officials stressed that those affected should act quickly, with the registration deadline just days away. Missing it could leave taxpayers facing avoidable penalties and added stress.

Who Needs to Register for Self Assessment?

HMRC uses the Self Assessment system to collect income tax from individuals who do not have all their income taxed at source. For employees paid through payroll, tax is usually deducted automatically. However, the system works differently for certain groups.

Those who are self-employed, landlords earning rental income, or partners in business partnerships are required to declare their income through a tax return. Registration is the first step to accessing the system, and HMRC has urged individuals to use its free online tool to check whether they fall within the scope.

The October 5 Deadline

The crucial deadline for new Self Assessment registrations is October 5. This date applies to those who became self-employed or started earning untaxed income in the previous tax year. If you miss the deadline and do not pay your full tax bill by January 31, HMRC may apply a ‘failure to notify’ penalty.

This penalty is based on the amount owed and is usually issued within a year of HMRC receiving the late return. While taxpayers can provide details of special circumstances for consideration, officials are clear that failing to act on time can result in significant costs.

What Happens If You File Late?

HMRC sets out a tiered penalty structure for late submissions. Initially, a £100 fine is issued as soon as the deadline is missed. If the return remains outstanding after three months, daily fines of £10 are added, up to a maximum of £900.

Further charges follow as delays continue. At the six-month point, HMRC applies either a penalty of 5% of the tax due or £300, whichever is greater. After twelve months, another charge of 5% or £300 is added. In total, the cost of failing to meet the deadlines can quickly escalate, particularly for those with higher liabilities.

Support Available for Taxpayers

For anyone struggling to meet their Self Assessment obligations, there are options available. Taxpayers can appoint a professional accountant or adviser like UK Property Accountants to file on their behalf, or alternatively nominate a trusted family member or friend to help manage the paperwork.

HMRC also offers direct support through its helpline and online chat service, where staff can provide guidance on completing forms and navigating the process. Officials emphasise that seeking help early is always better than leaving matters until after the deadline has passed.

Conclusion

With the October 5 registration date approaching rapidly, HMRC is reminding taxpayers that acting now is essential. For new business owners, landlords, or those earning untaxed income, this deadline marks the first step in staying compliant and avoiding unnecessary penalties.