Missing the self-assessment tax return deadline in the UK is stressful — but it’s fixable. Whether you forgot, faced unexpected issues, or didn’t know you had to file — here’s a comprehensive guide on what to do, how to avoid further penalties, and how Audit Consulting Group can help.
Key Self-Assessment Deadlines
- 31 January – Online tax return deadline and payment due date
- 5 October – Deadline to register for self-assessment if self-employed or earning untaxed income
Penalties for Late Filing
- £100 fine if you miss the deadline (even if you owe nothing)
- Additional fines if you’re more than 3 months late
- Daily penalties, interest, and surcharges if it remains unpaid
What to Do If You Missed the Deadline
- File Your Return ASAP – This stops further penalties from increasing.
- Pay Outstanding Tax – Interest begins accruing from 1 February.
- Appeal the Penalty – If you had a valid excuse (bereavement, illness, technical failure), you can write to HMRC with evidence.
Common Reasons for Late Submission
- Didn’t know you needed to file
- Issues gathering records
- Illness or emergency situations
How Audit Consulting Group Helps
- We can file your return even if you’re late
- We handle all communication with HMRC
- We can write and submit a penalty appeal letter for you
Our clients benefit from:
- Stress-free filing
- Faster processing
- Peace of mind knowing professionals are handling it
Prevent It Next Year
We offer ongoing support, deadline reminders, and annual planning to ensure you never miss another deadline.