Preparation for UK CBAM: Final Secondary Legislation and Technical Hurdles

As we reach the mid-point of 2026, the trade and customs industry is focusing heavily on the fast-approaching 1 January 2027 deadline for the UK Carbon Border Adjustment Mechanism (CBAM). This week, following the primary legislation established in the Finance Act 2026, HM Revenue and Customs (HMRC) and the Treasury have released the final technical guidance regarding the monitoring, reporting, and verification (MRV) of embedded emissions for in-scope goods. For TCSA members, this represents the final regulatory jigsaw piece before the implementation phase begins in earnest.

Finalized Scope and Thresholds

The latest updates confirm that the UK CBAM will initially apply to imports in the aluminium, cement, fertiliser, hydrogen, and iron and steel sectors. A significant point of discussion within the industry was the proposed inclusion of glass and ceramics; however, following extensive spring consultations, the government has reaffirmed that these sectors will remain out of scope for the 2027 launch. This decision offers temporary relief to specialists in those sectors, though the government has indicated a review will occur in 2030.

Another crucial clarification concerns the minimum threshold for compliance. The government has confirmed a 12-month registration threshold of £50,000 for the total value of CBAM-covered goods. This is a substantial increase from the initial £10,000 proposal, exempting thousands of smaller businesses and occasional importers. For customs brokers, this means a rigorous review of client portfolios is necessary to determine who meets this reporting obligation. It is important to note that the £50,000 limit is based on the value of the goods, not the tax liability, which simplifies the assessment process for trade compliance teams.

The Challenge of Verified Emissions Data

One of the most complex aspects of the new guidance released this week involves the hierarchy of emissions data. While HMRC will allow the use of 'government-determined default values' during the initial 2027 reporting period, these values are expected to be punitive. Importers who can provide 'actual emissions data'—verified by accredited third-party bodies—will likely face a lower CBAM liability. The secondary legislation clarifies that verification must be conducted by bodies accredited under ISO 14065 or by recognized national equivalent schemes in the country of origin.

This creates a significant administrative hurdle for freight forwarders and compliance officers. The task of gathering detailed, installation-level data from overseas producers is fraught with difficulty, particularly in regions where carbon accounting is less mature. TCSA members should advise their clients to begin the 'supplier mapping' process immediately to ensure that production sites are capable of producing the necessary data sets for the first annual return, due in May 2028. Failure to secure verified data early could lead to significant financial overpayments when the carbon price is applied.

Practical Implications for Trade Professionals

For the professional customs community, the UK CBAM is not merely a tax but a data management challenge. First, the liability for the CBAM return lies with the 'person responsible' for the import—typically the importer of record. However, as many importers will look to their customs agents for support, brokers must decide whether they will offer CBAM filing as a value-added service or restrict their role to providing the underlying import data. There are significant indemnity considerations to weigh here, as the complexity of carbon accounting far exceeds traditional tariff classification.

Second, the UK CBAM differs from its EU counterpart in several ways, including the frequency of reporting (initially annual, moving to quarterly from 2028) and the treatment of indirect emissions. The newly released guidance confirms that indirect emissions—those from electricity used during manufacturing—will be in scope for the UK scheme. This decision is aimed at aligning the CBAM with the UK Emissions Trading Scheme (ETS) and requires a deeper level of supply chain visibility than many currently possess. Logistics providers should prepare for potential delays if documentation regarding carbon intensity is missing or incomplete at the point of entry.

Strategic Next Steps

With only seven months until the scheme goes live, the TCSA recommends several immediate actions for its members:

  • Perform a historical audit of commodity codes to identify which clients are importing in-scope goods above the £50,000 threshold.
  • Engage with overseas suppliers to assess their readiness to provide verified emissions data and identify any accreditation gaps.
  • Review internal IT and customs software to ensure that CBAM-specific data elements—such as installation location and embedded carbon intensity—can be captured accurately.
  • Update terms and conditions for customs representation to clarify the scope of services regarding CBAM returns.

The transition to a greener trade landscape is no longer a future prospect; for the UK customs professional, the era of carbon-based border controls starts now. Stay tuned for our upcoming TCSA webinar series detailing the technical specifics of the new HMRC CBAM portal.