The UK CBAM emissions regulations are made: accreditation settled, return requirements extended

The United Kingdom completes the legal framework

On 8 September 2026, HM Treasury and HMRC made the Carbon Border Adjustment Mechanism (Emissions and Verification) Regulations 2026, and they were laid before the House of Commons on 9 September. They come into force on 1 January 2027 together with the UK CBAM itself. The last of the four announced pieces of secondary legislation is now in binding form. Compared with the April consultation draft, there are changes that manufacturers in the EU and importers in the United Kingdom should know about.

Who may accredit is now settled

In the draft, the condition that an accreditation body must be a full member of the Global Accreditation Cooperation Incorporated was still in square brackets. The made version adopts it without reservation and names the legal entity precisely, a society incorporated in New Zealand with the registration number 50223540. Behind this stands the merger of the two international accreditation associations IAF and ILAC, completed on 1 January 2026, which brings together national accreditation bodies such as UKAS or Germany's DAkkS.

In practice, this means the United Kingdom is building on the existing international accreditation system. A verifier accredited by one of these national bodies for the relevant type of good is eligible in principle. The verifier must additionally be independent of the importer, the producing installation and all precursor installations. Whether an existing EU CBAM accreditation is sufficient without a further step will be decided by a notice from HMRC that is still outstanding. EU manufacturers should ask their verifier now whether, and under which accreditation, it will offer UK verifications.

The return will ask for the default value and the verified intensity

The most important change compared with the draft sits in the final Part of the Regulations, which amends the Administrative Provisions Regulations already made in July. The CBAM return must in future contain three additional items per good. Where a default value is used, its level must be stated. Where actual emissions are used, the emissions intensity must be stated, and it must have been verified by a verifier. The return must also declare whether the good was produced using a precursor of UK origin, whose emissions are not taxed under the Act.

Also new is a record-keeping requirement for all business importers, regardless of the 50,000 pound registration threshold. Anyone relying on an exemption for UK origin or returned goods must document this for each good. The return thus becomes a control instrument. HMRC can check default value entries against its own notice and actual emissions entries against the verification report. Since a later switch from default values to actual emissions by amending the return remains excluded, the decision must be made for each good before filing.

Fewer records, but the verification report must be available

The draft required importers using actual emissions to hold seven separate records, including the installation address, the month of production, verifier details and the emissions intensity of every precursor. The made version streamlines this considerably. Only the verifier's verification report or a so-called good-specific verification summary must be kept, the content of which HMRC will still define by notice. The retention period is six years.

The verification report itself goes to the installation operator, not to the importer. It contains the installation, the operator, the verifier with accreditation number, the monitoring period and the verification opinion. The importer depends on the supplier passing on this report or the summary. The good-specific summary is likely to become the document that manufacturers routinely provide to their UK customers, similar to the emissions communication under the EU CBAM. Supply contracts and data requests should already provide for it.

Calculation close to the EU, with a relaxation for 2027

The calculation method for actual emissions is essentially unchanged from the draft. It starts at installation level, uses a calendar year as the monitoring period, adds precursor emissions and produces an emissions intensity per tonne rounded to five decimal places. The conversion factors for nitrous oxide and the two perfluorocarbons match those of the EU methodology. Anyone who will hold verified installation data for the EU CBAM therefore has the data basis for the United Kingdom as well, subject to the HMRC methodology notice that is still outstanding.

On the monitoring period, the made version is more generous than the draft. For imports in 2027, the most recent year with verified data from the year of import or the preceding year may be used, or alternatively the year of production. Verified data for 2026 is therefore sufficient for the whole of the first year. From 2028, the rule from the draft applies, namely the most recent verified year of the two preceding years or the year of production. A new addition is a special rule for so-called multifunctional goods, where the emissions intensity may be formed across a group of goods rather than per type of good. The conditions for this, and the conversion equation for cement and fertilisers, are still to be set by HM Treasury by notice.

Interest runs from the first due date

On the same day, HM Treasury made a second instrument (SI 2026/994). It brings the late payment and repayment interest provisions of sections 101 and 102 of the Finance Act 2009 into force for the UK CBAM from 1 January 2027, expressly including penalties. Under the HMRC formula, late payment interest is the Bank of England base rate plus four percentage points, and repayment interest is the base rate minus one percentage point, with a floor of 0.5 percent. This becomes practically relevant with the first due date on 31 May 2028, when the return and payment for the whole of 2027 fall due. Together with the late payment penalties already provided for in the Act, the enforcement toolkit of the UK CBAM is now complete.

Outlook

The Regulations refer in more than ten places to notices that HMRC and HM Treasury have yet to publish, including the default values, the measurement methodology, the requirements for verifiers and the definition of the good-specific verification summary. Until then, it remains open whether 2026 data collected under the EU methodology will be accepted without adjustment. EU manufacturers with UK customers should check in the coming weeks whether their 2026 monitoring delivers installation data per type of good in line with the System Boundaries Document, and whether their verifier holds an accreditation from a GAC member body. UK importers should ask their suppliers now for a commitment on emissions intensity and the verification report, before the registration deadline of 31 January 2028 draws closer.

Support

If you would like to understand how the made UK Emissions Regulations affect your CBAM processes, whether your existing EU installation data and verification are sufficient for imports into the United Kingdom, and what information your UK customers will need from you in future, please get in touch at helge@kolum.earth.