HMRC Wants a Self Assessment Tax Return? Here’s What to Know
- kjbinternational
- May 29
- 5 min read
Many self-employed individuals and small business owners in the UK have recently received a letter from HMRC (His Majesty’s Revenue and Customs) asking them to file a Self Assessment tax return for the tax year running from 6 April 2024 to 5 April 2025. If you received one of these letters, it does not necessarily mean you’ve done anything wrong. In fact, HMRC sends these letters out early as a reminder to help you plan ahead and avoid penalties.
In this article, we explain what the letter means, why you received it, what deadlines apply to you, and what to do next.
What Is the HMRC Self Assessment Tax Return Letter?
The HMRC letter you received is a notice informing you that you are required to complete a Self Assessment tax return for the current tax year (6 April 2024 to 5 April 2025). This is a legal requirement if you meet certain conditions. According to HMRC, you must file a tax return even if:
You have already paid all the tax you owe
You think you do not owe any tax
You have no new income to declare
The purpose of the letter is to give you advance notice so that you have plenty of time to prepare your records and submit your return.
Key Deadlines You Need to Know
Here are the important deadlines you should keep in mind:
5 October 2025: Deadline to register for Self Assessment if you’ve never submitted a return before
31 October 2025: Deadline to file a paper tax return
31 January 2026: Deadline to file your return online and pay any tax you owe
If you miss these deadlines, HMRC can issue financial penalties.
Penalties for Filing Late
If you do not file your tax return on time, you may face the following penalties:
One day late: £100 fine
Three months late: £10 per day (up to £900), in addition to the initial £100 fine
Six months late: £300 or 5% of the tax due (whichever is higher), plus earlier penalties
Twelve months late: An additional £300 or up to 100% of the tax owed, depending on the case
These penalties apply even if you do not owe any tax.
New Penalties for Late Payment in 2025
As of April 2025, the government has introduced stricter penalties for late tax payments, especially for those registered for Making Tax Digital.
Here’s how the new penalty system works:
If you pay within 15 days of the deadline > no penalty
If you pay between 16 and 30 days after the deadline > you will owe 3% of the tax you owe
If you pay after 30 days: Additional penalties apply. You could face penalties of up to 6% (3% at day 15 and 3% at day 30) and an ongoing daily penalty of 10% per year on the unpaid balance.
This is in addition to any interest HMRC charges on the late amount.
What If You Think You Don’t Need to File a Tax Return?
If you believe you do not need to file a Self Assessment return, you should contact HMRC as soon as possible. You must inform them before 31 January 2026. If HMRC agrees, they may cancel the requirement. If not, and you fail to file, you will still receive penalties.
You can use the tool on the HMRC website to check if you need to send a return by searching “check if you need to send a Self Assessment tax return” on GOV.UK.
How to File Your Tax Return
The easiest way to file your return is online. To do this, follow these steps:
Go to the GOV.UK website and search for “file your Self Assessment tax return online”
Sign in to your HMRC online account (or create one if you do not have one)
Follow the instructions and complete your return
Note: If you are in a partnership, live abroad, or need to file on behalf of a trust, estate, or religious organisation, you will need commercial software to submit your return online. HMRC provides a list of approved software providers.
Payment Options
You need to pay any tax you owe by 31 January 2026. If you cannot afford to pay in full, HMRC offers a “Time to Pay” service, which allows you to spread the cost over a longer period. You will still be charged interest, but this can help avoid further penalties.
What If You Receive a Penalty?
If you are fined for filing late or making a mistake, you may be able to appeal the penalty. HMRC allows appeals if you have what they consider a “reasonable excuse.” Examples include:
Serious illness or hospitalisation
A death in the family
Problems with your software or HMRC’s system
Fire, flood, or theft of documents
Disability-related delays
To appeal, you must either use the Self Assessment online portal or download form SA370 from GOV.UK and send it by post.
Common Reasons for Receiving a Penalty
HMRC may issue a penalty for the following reasons:
Filing your return late
Paying your tax bill late
Failing to keep accurate financial records
Making mistakes on your return
Not declaring all your taxable income
Mistakes made due to carelessness or attempts to avoid paying the correct amount of tax may result in higher penalties.
What If You Disagree with HMRC?
If your appeal is unsuccessful, you can ask HMRC for a review or take your case to a tax tribunal. Alternatively, you can use a mediation process called Alternative Dispute Resolution (ADR) to try to resolve the issue without going to court.
Final Thoughts
Receiving a letter from HMRC can be worrying, but in most cases, it is simply a reminder of outstanding or upcoming tax obligations. It gives you time to get organised and avoid fines. Make sure you keep good financial records, check deadlines regularly, and seek help if you are unsure.
If you are self-employed, part of a partnership, or running a small business, staying informed is one of the best ways to protect yourself from unnecessary penalties and stress.
At KJB International Aid, we are here to support you with clear guidance, helpful tools, and practical support. Whether you need help filing your return, understanding your responsibilities, or dealing with penalties, we’re here to help.
KJB International Aid Ltd.
WhatsApp: +44 7305464275
Email: info@kjbinternationalaid.com
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