What happens if I don't file a Tax Return?
Unlike other debts where you can negotiate, HMRC penalties are automatic and set in law. Even if you owe NO tax, you will still be fined heavily just for not sending the form. The system is designed to punish delay.
1 The Typical Timeline
If you take no action, this is the standard statutory process. Timescales are approximate but typical for 2026.
31st January
The deadline for online returns. If you miss this by 1 minute, you receive an automatic £100 fine.
Daily Penalties Start
This is the trap. You are charged £10 per day, every day, for 90 days. This adds £900 to your bill automatically.
5% Surcharge
Another penalty of £300 (or 5% of tax due) is added. You now owe at least £1,300 in fines alone.
Doubled Surcharge
Yet another 5% charge. If HMRC thinks you are 'withholding information', this can rise to 100% of the tax due.
2 Free Calculators & Checks
The numbers get scary fast. Use this calculator to see exactly how much you owe in fines right now.
Penalty "Doom" Calculator
See how quickly a £100 fine becomes £1,600+. Penalties apply even if you owe NO tax.
Usually 31st Jan
Thinking of appealing? Take this quiz first to see if HMRC will likely accept your excuse.
Can I appeal the fine?
HMRC only accepts specific "Reasonable Excuses". Check if yours counts.
Need to appeal? This tool generates a template letter for you based on your specific excuse.
Appeal Letter Generator
Create a formal appeal letter in seconds. Copy and paste into the HMRC appeal form.
The 'Reasonable Excuse' Rule
HMRC will cancel penalties if you have a 'Reasonable Excuse'. This is strictly defined. It generally means an unexpected event outside your control that stopped you from filing. Losing your password, trusting your accountant, or having no money are NOT valid excuses.
Summary of Options
File Immediately
Even if you can't pay the tax bill, FILE THE RETURN. This stops the late filing penalties (Daily £10s) from growing.
Appeal Penalties
If you had a 'Reasonable Excuse' (death in family, flood, fire, hospital stay), you can appeal. 'I forgot' or 'Couldn't pay' are NOT valid excuses.
Time to Pay
Once you have filed, call the Payment Support Service to set up a monthly payment plan for the tax owed.
Common Questions
Can I go to prison for not filing?
For simple late filing? No. You just get huge fines. Prison is for 'Tax Evasion' (lying about income or deliberately hiding money), which is a criminal offence.
I have no money to pay the tax. Should I delay filing?
ABSOLUTELY NOT. This is a common disaster. The penalty for late filing is separate from late payment. If you file now, you stop the £10 daily fines. You can then negotiate a payment plan for the tax.
My accountant didn't file it. Is it my fault?
Yes. In law, it is YOUR responsibility. You have to pay the fine, but you could then sue your accountant for negligence to get the money back.
Official Sources & References
Related Situations
Other guides accurately explaining what happens next in tax & hmrc .
What happens if HMRC freezes my bank account?
HMRC has two ways to stop your cash: Civil debt collection (DRD) or Criminal investigation (AFO). Know which one you are facing and how to protect your living costs.
What happens if I don't respond to a letter from HMRC?
Ignoring HMRC is dangerous. They can 'determine' (guess) your tax bill and charge daily penalties for silence.
What happens if I'm reported to HMRC?
Being reported for tax evasion is stressful. HMRC's 'Connect' system will analyse your data. If you have undeclared income, telling them BEFORE they investigate reduces penalties significantly.