Appealing a CIS penalty - what counts as a reasonable excuse

If you receive a penalty for late CIS returns or late payment of CIS deductions, you can appeal if you have a reasonable excuse. This guide explains what HMRC considers a reasonable excuse, how to appeal, and what evidence you need.

Understanding what constitutes a valid reason for appeal can save you from paying penalties you do not deserve - but it also helps you recognise when an appeal is unlikely to succeed.

When you can appeal a CIS penalty

You can appeal a CIS penalty if:

• You had a reasonable excuse for the failure (late filing or late payment)
• You believe the penalty has been calculated incorrectly
• You believe you should not have received the penalty (for example, you filed on time but HMRC did not receive it)

A reasonable excuse is something unexpected or outside your control that stopped you from meeting your CIS obligations on time. HMRC considers each case individually, but there are clear patterns of what they accept and reject.

Understanding CIS penalties

Before appealing, understand what penalty you have received and how it was calculated. CIS penalties escalate the longer you delay, so a quick appeal is important.

What HMRC accepts as a reasonable excuse

HMRC publishes guidance on what typically constitutes a reasonable excuse. The key principle is that the excuse must be genuine, unexpected, and directly cause the failure.

Real examples: accepted and rejected appeals

These examples illustrate how HMRC applies the reasonable excuse criteria in practice:

Appeals HMRC accepted

• Heart attack the week before deadline: Contractor suffered a heart attack 5 days before the return was due and was hospitalised for 10 days. Medical evidence provided. Appeal upheld - serious illness was unexpected and directly prevented compliance.
• Office fire destroyed records: Fire at business premises destroyed computer equipment and paper records 3 days before deadline. Fire service report and insurance claim provided. Appeal upheld - disaster was unexpected and records could not be recreated in time.
• HMRC online service was unavailable: Contractor attempted to file on 19th but received error messages. Screenshots showing attempts between 6pm and 11pm provided. Service status confirmed outage. Appeal upheld - HMRC system failure prevented timely filing.
• Death of spouse one week before deadline: Contractor's spouse died unexpectedly 8 days before return due. Bereavement affected ability to handle business matters. Death certificate and statement provided. Appeal upheld - recent bereavement is a recognised reasonable excuse.

Appeals HMRC rejected

• Accountant did not file on time: Contractor said accountant promised to file but forgot. HMRC rejected - responsibility remains with the contractor, and relying on someone else is not a reasonable excuse.
• Too busy with other work: Contractor said a large project meant they did not have time to file. HMRC rejected - pressure of work is not unexpected and deadlines are known in advance.
• Did not know about the deadline: New contractor claimed ignorance of filing requirements. HMRC rejected - ignorance of obligations is not a reasonable excuse. Information is publicly available.
• Computer crashed, lost data: Contractor's computer failed but they had no backups. HMRC rejected - routine IT problems are foreseeable. Businesses should have backup systems.
• Cash flow problems: Contractor could not pay accountant to file returns. HMRC rejected - financial difficulties do not excuse late filing (though may be considered for payment penalties in limited circumstances).
• Staff member left without notice: Person responsible for CIS returns resigned unexpectedly. HMRC rejected - businesses should have contingency plans. Staff turnover is foreseeable.

The appeal process

Appeals must follow a specific process with strict deadlines. Missing deadlines can make your appeal invalid.

Step-by-step: how to appeal

Writing an effective appeal

Your appeal letter should be clear, factual, and supported by evidence. Here is a structure that works:

What to include

1. Your details: Full name, business name, UTR, and CIS contractor reference
2. Penalty reference: The reference number from your penalty notice
3. What happened: A brief, factual description of the event that prevented compliance
4. Why it was beyond your control: Explain why you could not have foreseen or prevented it
5. When you complied: State when you filed the return or paid the deductions after the excuse ended
6. Evidence attached: List the documents you are including

Example appeal letter opening

"I am writing to appeal the late filing penalty of [amount] dated [date], reference [penalty reference], relating to the CIS return for tax month [period].

On [date], I was admitted to hospital following a heart attack. I was unable to work or access my business records until [date]. As soon as I was discharged and able to work, I filed the return on [date]. I attach a letter from my GP confirming the dates of my illness and hospital admission."

What happens after you appeal

If HMRC accepts your appeal

The penalty is cancelled. If you have already paid it, HMRC will refund the amount to your CIS account or bank account.

If HMRC rejects your appeal

You have two options:

• Request an internal review: Ask for a different HMRC officer to look at your case. This is free and can sometimes succeed where the first appeal failed.
• Appeal to the Tax Tribunal: You have 30 days from HMRC's final decision to appeal to the First-tier Tax Tribunal. Tribunal appeals are independent of HMRC.

Tribunal appeals

The First-tier Tax Tribunal is independent of HMRC. You can represent yourself or use a tax adviser. For small penalties, the tribunal uses a paper-based process - you do not need to attend a hearing.

There is no fee to appeal to the First-tier Tribunal (Tax Chamber), whatever the size of the penalty or the category your case is allocated to.

Multiple penalties and appeals

If you have received penalties for multiple late returns, you must appeal each penalty separately. However, if the same reasonable excuse applies to all penalties (for example, a period of illness), you can include them all in one letter.

State clearly which penalty references you are appealing and confirm that the same excuse applies to each one.

Preventing future penalties

After dealing with the immediate penalty, take steps to avoid future problems:

• Set calendar reminders: The 19th of each month is your filing deadline. Set reminders for the 15th and 18th.
• File early: Do not wait until the 19th. Filing by the 14th gives you a buffer for problems.
• Request inactivity in advance: If you will not pay subcontractors for a period, tell HMRC at least 14 days before the start of the tax month (an inactivity request covers up to 6 months). Otherwise you must file a nil return for each month with no payments.
• Use software: Payroll software can automate CIS returns and send reminders.
• Have a backup plan: Ensure someone else in your business can file returns if you are unavailable.