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By Missing a tax deadline in the UK can be more costly than many business owners realise. Whether you’re a sole trader, landlord, freelancer, or limited company, late submissions can trigger automatic penalties, interest charges, and unwanted attention from HMRC.
At TT Accountancy Services (TTAS), we help UK businesses stay compliant, avoid penalties, and resolve issues quickly when deadlines are missed. In this guide, we explain what happens if you miss a UK tax deadline, the penalties involved, and what to do next.
Why Tax Deadlines Matter in the UK
The UK tax system relies heavily on timely self-reporting. HMRC uses automated systems to track deadlines and issue penalties without warnings.
Missing a deadline can affect:
- Your cash flow
- Your business credibility
- Your stress levels
- Your future dealings with tax authorities
The key authority involved is HM Revenue & Customs (HMRC).
1. Missing a Self-Assessment Tax Deadline
Key Deadlines
- 31 October – Paper tax return
- 31 January – Online tax return & tax payment
What Happens If You Miss It?
- Immediate £100 penalty, even if you owe no tax
- After 3 months: £10 per day (up to £900)
- After 6 months: Additional £300 or 5% of tax owed
- After 12 months: Another £300 or 5% of tax owed
Interest also accrues daily on unpaid tax.
Commonly affects: sole traders, landlords, freelancers, company directors.
2. Missing a Corporation Tax Deadline (Limited Companies)
Key Deadlines
- Corporation Tax payment: 9 months + 1 day after accounting period
- Company Tax Return (CT600): 12 months after accounting period
Penalties for Late Filing
- £100 fine (1 day late)
- Another £100 fine after 3 months
- 10% surcharge on unpaid tax after 6 months
- Another 10% surcharge after 12 months
Late payments also attract interest charges.
3. Missing a VAT Deadline
VAT operates on strict quarterly deadlines.
Consequences
- Entry into HMRC’s VAT penalty points system
- £200 penalty once threshold points are reached
- Late payment penalties (up to 4% of VAT owed)
- Interest charged daily
Frequent late submissions increase HMRC scrutiny.
4. Missing Payroll (PAYE) Deadlines
If you employ staff, payroll deadlines are non-negotiable.
Common Penalties
- £100–£400 monthly fines (depending on staff size)
- Late RTI submissions flagged automatically
- Interest and penalties on late PAYE payments
Payroll errors can also damage employee trust.
5. Missing Companies House Deadlines
Missing annual accounts deadlines with Companies House can result in:
- £150 to £1,500 in penalties
- Doubled penalties for repeat offences
- Risk of company strike-off if ignored
This is separate from HMRC penalties.
What If You Keep Missing Deadlines?
Repeated late filings can lead to:
❌ HMRC compliance checks
❌ Tax investigations
❌ Higher scrutiny of future returns
❌ Difficulty obtaining loans or contracts
❌ Damage to your business reputation
What to Do If You’ve Missed a Tax Deadline
If you’ve already missed a deadline, don’t panic — but act quickly:
- Submit the return immediately (penalties stop increasing)
- Pay as much tax as possible to reduce interest
- Contact HMRC or your accountant
- Check if you qualify for a reasonable excuse appeal
- Set up a Time to Pay arrangement if needed
Professional guidance can make a big difference at this stage.
How TT Accountancy Services Can Help
At TTAS, we help clients:
- File late tax returns correctly
- Minimise penalties and interest
- Appeal unfair penalties
- Communicate with HMRC on your behalf
- Set up Time to Pay arrangements
- Create systems to never miss deadlines again
We manage:
✔ Self-Assessment
✔ VAT returns
✔ Payroll & PAYE
✔ Corporation Tax
✔ HMRC correspondence
Need urgent help with a missed deadline?
Contact TT Accountancy Services today.
Missing a tax deadline in the UK can be expensive — but the damage can often be limited with fast action and professional support.
The best approach is prevention:
✔ Accurate records
✔ Clear deadlines
✔ Professional oversight
With TT Accountancy Services, you stay compliant, penalty-free, and focused on growing your business — not worrying about HMRC letters.
