The CIS verification number, explained
When you verify a subcontractor, HMRC gives you a verification number. Here is what it looks like, what the letters at the end mean, and where it must appear.
What it is
When HMRC verifies a subcontractor, it gives you, the contractor, a verification reference number. The number is the same for every subcontractor verified for you at the same time. Source: Construction Industry Scheme: a guide for contractors and subcontractors (CIS 340).
What it looks like
HMRC's guide gives the example V0004528765: the letter V, then digits. Where HMRC cannot verify a subcontractor, it adds one or two letters to the end of the number so that it is unique to that subcontractor, as in V0004528765/A. Source: Construction Industry Scheme: a guide for contractors and subcontractors (CIS 340).
| What you see | What it means | Deduction |
|---|---|---|
| The number alone, for example V0004528765 | HMRC matched the subcontractor and told you the rate | 20%, or 0% with gross payment status |
| The number with letters added, for example V0004528765/A | HMRC could not verify the subcontractor | 30%, the higher rate |
Source: Construction Industry Scheme: a guide for contractors and subcontractors (CIS 340); What you must do as a CIS contractor: make deductions and pay subcontractors.
Where you must show it
Where you deduct at the higher rate, you must show the verification number on your monthly return, next to that subcontractor, and on the payment and deduction statement you give them. Source: Construction Industry Scheme: a guide for contractors and subcontractors (CIS 340). See what the payment and deduction statement must show.
When you get one
- Before you first pay a new subcontractor, you must verify them with HMRC.
- You verify again anyone you have not included on a CIS return in the current tax year or the last 2.
- Temporary National Insurance numbers, which start with TN or 2 digits, cannot be verified.
Source: What you must do as a CIS contractor: verify subcontractors. The steps are in how to verify a subcontractor with HMRC.
It is not the subcontractor's UTR
To verify a subcontractor you give HMRC their Unique Taxpayer Reference (UTR). The verification number is different: it is the reference HMRC gives you for that verification. Source: What you must do as a CIS contractor: verify subcontractors; Construction Industry Scheme: a guide for contractors and subcontractors (CIS 340).
What we suggest you keep
Our suggestion, not an HMRC rule: one record for everyone you pay, with the date you verified them, the verification number and the rate HMRC gave. Keep your CIS records for at least 3 years after the end of the tax year they relate to. Source: What you must do as a CIS contractor: record keeping.
Questions people ask
What does the letter at the end of a CIS verification number mean?
HMRC adds one or two letters to the end of the number when it cannot verify a subcontractor, so that the number is unique to them. You then deduct at the higher rate of 30%.
Do I show the verification number on every payment and deduction statement?
Only where you deducted at the higher rate. Then the number goes on your monthly return and on the subcontractor's statement.
Is the verification number the same as a UTR?
No. The UTR is the subcontractor's own tax reference, which you give HMRC to verify them. The verification number is the reference HMRC gives you for that verification.
Read on GOV.UK on 28 October 2026. If GOV.UK changes, we change this page.
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