Under UK CBAM, a number only counts if someone independent has checked it. That makes the verifier one of the most important, and least understood, people in the process. A supplier who pays the wrong kind of verifier can end up with a report their customer cannot use.
Why the verifier matters
Without verified data, an importer falls back on the published default value for the product. To claim Carbon Price Relief, the importer needs a carbon pricing verification form, and HMRC will not accept a form that has not been completed by a verifier who meets its conditions. If the form is missing or the verifier does not qualify, no relief can be claimed.
In both cases the importer, not the supplier, carries the risk of an unusable document. That is why UK customers are likely to ask suppliers who their verifier is before they ask for the numbers.
What HMRC requires
For the carbon pricing verification form, HMRC says the verifier must, at the time of verification, meet all of the following:
- Be accredited by an accreditation body that is a full member of the Global Accreditation Cooperation (Global ACI).
- Be a signatory to the Global Accreditation Cooperation Multilateral Recognition Agreement.
- Be independent of the site, the importer and the country running the carbon pricing scheme.
- Be accredited to all four of these standards: ISO/IEC 17029:2019, ISO 14064-3:2019, ISO 14065:2020 and ISO 14066:2023.
| ISO/IEC 17029 | General principles and requirements for bodies that validate and verify |
| ISO 14064-3 | How to verify and validate greenhouse gas statements |
| ISO 14065 | Requirements for bodies that validate and verify environmental information |
| ISO 14066 | Competence needed by the teams doing the verification |
Accreditation is the test, not a good reputation. A verifier is either accredited to these standards, by the right kind of body, or the form is not accepted.
How to check a verifier
- Ask for their accreditation certificate and note the name of the accreditation body.
- Check that body appears among the full members listed on the Global ACI website.
- Read the certificate's scope. It must cover all four standards, not just one.
- Confirm the verifier has no ownership, advisory or commercial tie to your site, your UK customer or the scheme's administrator.
- Keep a copy of all of this on file. Your customer will need it.
Questions to ask before you pay
Before you engage a verifier
- Are you accredited to all four standards, and can I see the certificate?
- Will the form meet HMRC's conditions for the scheme I operate under?
- Have you verified for UK CBAM goods in my sector before?
- What data will you need from my site, and in what format?
- If another firm prepared our data, does that affect your independence?
Before you accept a form
- Has the form been completed in full, with emissions split by scheme element?
- Does the verifier's accreditation cover every required standard, and was it valid on the verification date?
- Is the emissions year one of the two calendar years before import?
- Do you hold a copy, as you will need to keep records?
What this does not cover
The conditions above are HMRC's, for the carbon pricing verification form used to claim Carbon Price Relief. Verifying a product's emissions data to replace a default value follows the UK monitoring, reporting and verification rules, which HMRC set out in separate technical guidance that was still open for feedback when we last checked. Read that guidance, or ask your verifier, before assuming the same terms apply.
Driftwatch does not verify emissions. Our work sits before verification: collecting and organising your production, fuel and process data so a verifier can work quickly and your customer receives something they can use.
Based on HMRC guidance on GOV.UK: Get a carbon pricing verification form (published 16 July 2026) and Claiming Carbon Price Relief. Last checked 22 October 2026. This is general information, not legal or tax advice. Check GOV.UK for the current position.