Report Construction Industry Scheme (CIS) contractor monthly return errors if you've received a letter from HMRC
Tell HMRC about an error if they’ve sent you a letter about applying an incorrect rate to your subcontractor payments in tax year 2025 to 2026.
HMRC are sending letters to contractors they believe may have applied an incorrect rate to their subcontractor payments between 6 April 2025 and 5 April 2026.
The letter:
- explains why HMRC thinks there may be an error
- tells you how to correct the error
- if appropriate, helps you work out any tax you owe
If you have not received a letter, use the HMRC CIS online service to tell HMRC that you need to change or correct something on your return. If you need to speak to someone, you can call the Construction Industry Scheme: general enquiries team.
When to use this form
Use this form to:
- tell HMRC how much tax you’ve underpaid, including how you’ve calculated it
- give details of other errors that can be corrected
- explain why you believe your returns are correct if you disagree with HMRC’s findings
HMRC will review the information you’ve given and decide whether you need to pay. However, you should still make a disclosure.
Who should use this form
You can use this form if you’re:
- an individual
- a designated member of a limited liability company
- a trustee of a trust
- a representative of an estate
- an officer of a company
- an agent
If you’re an agent, make sure you are authorised to make a disclosure on behalf of the business or company.
What you’ll need
You’ll need:
- your business name
- your Unique Taxpayer Reference (UTR)
- the letter we sent you, including the reference number from the letter (this will start with CFSS)
- details of any underpaid tax you owe for tax year 2025 to 2026
Complete the form
What happens next
HMRC will review the information you’ve provided and aim to contact you within 28 working days.