The UK Carbon Border Adjustment Mechanism (CBAM) is one of the most significant trade policy developments since Brexit. Starting 1 January 2027, it will impose a carbon cost on imports of carbon-intensive goods — reshaping supply chains and compliance obligations for thousands of UK importers.

What is UK CBAM?

CBAM is designed to ensure that imported goods face a carbon price equivalent to what UK producers pay under the UK Emissions Trading Scheme (UK ETS). Without such a mechanism, domestic manufacturers subject to carbon pricing would be undercut by overseas competitors operating in countries with weaker climate regulations — a phenomenon known as carbon leakage.

The UK CBAM mirrors, but is distinct from, the EU CBAM which began its transitional phase in October 2023. UK businesses trading with both markets will need to understand both frameworks to maintain compliance.

Sectors in Scope

Following extensive government consultation, the following sectors fall within UK CBAM from 1 January 2027:

• Aluminium — primary and secondary, including certain fabricated products
• Cement — clinker and finished cement products
• Fertilisers — nitrogen-based, including ammonia and urea
• Hydrogen — electrolytic and other forms
• Iron and Steel — including tubes, pipes and certain downstream products

Importantly, glass and ceramics were removed from the scope following the consultation process — a significant reprieve for importers in those sectors who had anticipated being captured by the regime.

Registration and Thresholds

Not every importer will be required to register. The registration threshold is set at £50,000 of CBAM-liable goods per calendar year. Businesses that import above this value must register with HMRC prior to the scheme’s implementation date.

For CBAM compliance support, working with an experienced customs intermediary is strongly recommended — particularly for businesses dealing with multiple product codes across different CBAM sectors.

Reporting and Returns

The CBAM returns schedule is structured as follows:

• First return deadline: 31 May 2028 (covering Q1 2028: 1 Jan – 31 Mar 2028)
• Quarterly returns: mandatory from 1 January 2028 onwards
• Record-keeping: minimum 6 years from the import date

Each return must declare the embedded carbon in imported goods, calculated using methodologies to be specified by HMRC. Where actual emissions data is unavailable, default values set by the government will apply — typically at higher rates, incentivising companies to obtain verified data.

Preparing Your Business for 2027

The window between now and January 2027 is critical. Businesses should take the following steps immediately:

• Audit your import portfolio to identify CBAM-liable commodity codes.
• Engage with suppliers to obtain embedded carbon data.
• Assess whether your annual import value crosses the £50,000 threshold.
• Review your IT and ERP systems for CBAM reporting capability.
• Consider engaging a specialist adviser for CBAM registration help.

Government Source

The authoritative source for all CBAM policy details is: GOV.UK — CBAM Policy Summary.