HM Revenue & Customs (HMRC), Britain’s tax authority, updated its official policy summary on 2 November, clarifying how importers must calculate Carbon Price Relief under the forthcoming UK Carbon Border Adjustment Mechanism (CBAM). The mechanism enters into force on 1 January 2027 and covers selected imports of steel, aluminium, cement, fertilisers and hydrogen. The relief allows qualifying foreign carbon costs to reduce an importer’s UK CBAM liabilities.
HMRC’s guidance requires importers to use emissions consistent with those used to calculate the carbon charge when determining the relief. They must establish the effective qualifying foreign carbon price after accounting for compensation, rebates and other adjustments, then apply that price to the relevant embedded emissions.
Where production involves multiple installations, precursor materials or different carbon-pricing arrangements, the corresponding emissions and payments may need to be treated separately. The rules do not allow companies to multiply total product emissions by the headline rate of a national carbon tax or emissions-trading scheme. HMRC’s guidance reflects that actual payments can be lower than nominal prices, particularly when free allowances or compensation are available.
Relief depends on costs and evidence
Britain’s published provisional list of qualifying schemes includes the Serbia Carbon Tax and the Montenegro Emissions Trading Scheme. Inclusion on the list does not automatically make every manufacturer in either country eligible for a deduction: the emissions must have incurred a qualifying carbon cost.
Importers must provide sufficient supporting documentation, and independent verification is required for carbon-price evidence used in a relief claim. For Serbian steel and aluminium suppliers, the rules link domestic tax records and production emissions to the competitiveness of exports to Britain. Montenegrin industrial producers face similar requirements where emissions covered by their domestic scheme can be linked to specific exported goods.
HMRC’s guidance means British customers need product-specific data that enables the effective carbon price to be calculated; generic certificates showing participation in an emissions scheme are not enough. Banks financing industrial exporters should not treat a potential deduction as a secure commercial benefit until eligibility and documentation have been established.
The update clarifies calculation rules but introduces no new exemption and does not postpone the January 2027 start date.