UK CBAM compliance becomes a legal obligation for UK importers on January 1, 2027, giving businesses fewer than 9 months to register, calculate embedded carbon in their imported goods, and prepare to pay the UK carbon price equivalent directly to HMRC. Unlike the EU carbon border adjustment mechanism, which operates through a certificate purchase system linked to EU ETS prices, UK CBAM is a tax-based mechanism where importers pay a direct financial charge, not surrender tradeable certificates. This distinction matters for every compliance strategy UK importers adopt.
This guide covers the 6 core compliance steps UK importers must complete, the goods and sectors in scope, how embedded carbon calculations work, and what penalties apply to non-compliant importers.
Caption: UK CBAM applies a tax-based charge on embedded carbon in imports from January 1, 2027, requiring UK importers to register and calculate carbon liabilities before the deadline.
What Is UK CBAM and Who Must Comply?
UK CBAM is a direct tax charge applied to the embedded greenhouse gas emissions of carbon-intensive goods imported into Great Britain, administered by HMRC and priced against the UK Emissions Trading Scheme (UK ETS) carbon price. UK importers, not foreign exporters, bear the legal compliance obligation.
The UK CBAM guide sets out the full legislative framework. For compliance purposes, the key boundary is this: any UK business that imports goods falling within the six covered sectors, above the applicable volume threshold, must register with HMRC before the charge takes effect.
Which UK Importers Are in Scope?
UK CBAM applies to UK-based importers who bring any of the following six categories of goods into Great Britain from any country (with limited exemptions for goods already subject to an equivalent carbon price). The 6 covered sectors are listed below.
The 6 UK CBAM sectors subject to the tax-based charge from January 1, 2027 are as follows.
- Aluminium (primary and secondary products, including unwrought aluminium and aluminium articles)
- Cement (clinker, Portland cement, and aluminous cement)
- Ceramics (bricks, tiles, and refractory products used in industrial processes)
- Fertilizers (urea, ammonia, and nitric acid-based compounds)
- Glass (flat glass, container glass, and glass fibre)
- Iron and steel (pig iron, direct-reduced iron, hot-rolled and cold-rolled products, pipes and tubes)
UK CBAM covers ceramics and glass in addition to the EU's six sectors, making the UK scope broader than the EU CBAM scope on initial implementation.
UK CBAM vs EU CBAM: The Critical Tax vs Certificate Distinction
UK importers pay a direct tax to HMRC based on embedded carbon content, calculated using the UK ETS carbon price. EU importers purchase tradeable CBAM certificates priced against the EU ETS. These are fundamentally different mechanisms: UK CBAM creates a tax liability; EU CBAM creates a certificate surrender obligation.
The distinction matters for cash flow planning, accounting treatment, and the double-payment risk for UK businesses that also export into the EU. For a full technical comparison, see UK CBAM vs EU CBAM.
6 UK CBAM Compliance Steps for UK Importers
The 6 compliance steps for UK importers to meet the January 1, 2027 deadline are outlined below. Steps 1 through 3 must be completed before the first import under the new regime; steps 4 through 6 are ongoing obligations.
Step 1: Determine Whether Your Imports Are in Scope
Confirm whether any goods you currently import fall within the 6 covered sectors using the commodity codes specified in the UK CBAM legislation. The determination uses the same CN code logic applied in EU CBAM. Goods produced in countries with a carbon pricing scheme recognized by the UK government may qualify for a reduced tax charge, but this recognition list is not yet finalized as of April 2026.
Step 2: Register With HMRC as a UK CBAM Importer
UK importers must register with HMRC before importing covered goods after January 1, 2027. Registration is expected to open via the HMRC online portal in Q3 2026, though the precise date has not been confirmed. Failure to register before importing covered goods exposes the importer to penalties applied to every tonne of embedded carbon in unregistered imports.
Step 3: Obtain Embedded Carbon Data From Your Suppliers
UK importers must obtain the embedded carbon intensity (expressed in kilograms of CO₂ equivalent per tonne of product) for each imported good from the producing installation. UK CBAM uses actual verified emissions where available. Where actual emissions data cannot be obtained, UK CBAM applies default values published by the UK government, which carry a mark-up above the country average to incentivize actual measurement.
Embedded carbon data must cover direct emissions from the production process. For ceramics, cement, glass, and fertilizers, indirect emissions from electricity consumption in production are also included in the calculation.
Step 4: Calculate Your UK CBAM Tax Liability
UK importers calculate their annual CBAM tax charge using this formula.
UK CBAM tax charge = Embedded carbon (tCO₂e) x UK ETS carbon price (GBP/tCO₂e) x Applicable reduction rate
The applicable reduction rate accounts for any carbon price already paid in the country of origin. If the exporting country has no recognized carbon pricing scheme, the full UK ETS price applies. The UK ETS carbon price as of April 2026 is approximately GBP 35-40 per tonne of CO₂ equivalent, though this fluctuates with market conditions.
Step 5: Submit Your Annual UK CBAM Return
UK importers submit an annual return to HMRC reporting the total embedded carbon in covered imports and the tax charge due. The annual return deadline is expected to be 31 May of the year following the import period, though the exact date will be confirmed in secondary legislation. The first return covers imports during calendar year 2027, due by 31 May 2028.
Step 6: Pay the UK CBAM Tax Charge
UK importers pay the CBAM tax charge directly to HMRC with the annual return. Payment is a direct tax settlement, not a certificate transaction. This is the fundamental operational difference from EU CBAM compliance, where importers purchase CBAM certificates from a central registry managed by DG TAXUD.
How to Calculate Embedded Carbon for UK CBAM
UK CBAM embedded carbon calculations use the same core principle as EU CBAM: the total greenhouse gas emissions released during the production of the imported goods, expressed in tonnes of CO₂ equivalent per tonne of product.
The 3 data sources UK importers can use to determine embedded carbon intensity are described below.
- Verified actual emissions: Data from the producing installation, verified by an accredited third-party verifier under the UK CBAM verification framework. This produces the most accurate liability and avoids the default value mark-up.
- UK government default values: Published country-specific and product-specific default values with a mark-up above the country average. The default mark-up schedule has not been finalized, but UK government consultation documents signal alignment with the EU approach of increasing mark-ups over time.
- Transitional estimates: For the 2027 import year, UK government guidance is expected to allow the use of verified EU CBAM embedded carbon data from the same installation as a transitional measure, given the overlap in scope and methodology.
Caption: UK importers have 3 options for sourcing embedded carbon data: verified actual emissions, default values, and transitional estimates for the first compliance period.
UK CBAM Compliance Timeline: Key Dates for UK Importers
The table below summarizes the critical dates UK importers must track for UK CBAM compliance.
| Milestone | Expected Date | Action Required |
|---|---|---|
| HMRC registration portal opens | Q3 2026 (exact date TBC) | Register as a UK CBAM importer |
| UK CBAM takes effect | January 1, 2027 | All covered imports subject to charge |
| First annual return deadline | May 31, 2028 (TBC) | Submit return for 2027 imports |
| First tax payment due | May 31, 2028 (TBC) | Pay CBAM charge to HMRC |
| Secondary legislation finalized | Expected H2 2026 | Confirm rates, thresholds, procedures |
UK importers should begin supplier engagement now, requesting embedded carbon data for all goods that fall within the 6 covered sectors, as obtaining verified emissions data from non-UK production installations can take 3-6 months.
UK CBAM Penalties for Non-Compliant Importers
UK importers face financial penalties for 3 categories of non-compliance: failure to register, failure to submit a return, and underreporting of embedded carbon. The UK CBAM penalty framework is expected to mirror the graduated structure of the EU CBAM penalty regime, though the exact penalty rates per tonne of CO₂ equivalent have not yet been confirmed in legislation as of April 2026.
The EU CBAM penalty for an authorized declarant who fails to surrender sufficient certificates is EUR 100 per tonne of CO₂ equivalent. For unauthorized importers, the EU penalty escalates to EUR 300-500 per tonne (3-5 times the standard rate). UK CBAM penalty rates are expected to be set at comparable levels in GBP.
How UK CBAM Differs From EU CBAM for Compliance Purposes
UK CBAM compliance and EU CBAM compliance share the same policy objective: pricing the embedded carbon content of imported goods at a level equivalent to the domestic carbon price. The compliance mechanics, however, are different across 4 key dimensions.
| Compliance dimension | UK CBAM | EU CBAM |
|---|---|---|
| Mechanism type | Tax-based: direct payment to HMRC | Certificate-based: purchase and surrender via CBAM Registry |
| Administering body | HMRC | National competent authority + DG TAXUD |
| Carbon price reference | UK ETS price | EU ETS auction clearing price |
| Sectors covered | 6 sectors including ceramics and glass | 6 sectors (no ceramics or glass) |
| Importer status | HMRC registration | Authorized CBAM declarant status |
| Payment timing | Annual lump sum with return | Ongoing certificate purchases; quarterly holding requirement |
| Certificate trading | No certificates; no secondary market | CBAM certificates transacted in central registry |
The tax-based structure of UK CBAM simplifies one aspect of compliance (no certificate inventory management) but concentrates the full payment obligation into a single annual tax event. EU importers spread their certificate purchases across the calendar year to meet the quarterly holding requirement of at least 50% of cumulative embedded emissions.
Contextual Border: How UK CBAM Fits Within the Broader Carbon Border Landscape
UK CBAM exists within a global trend toward carbon border measures, but UK importers must treat it as a distinct obligation from the EU CBAM. Goods entering Great Britain face the UK tax-based CBAM charge; the same goods entering the EU face the certificate-based EU CBAM obligation. These obligations apply independently and are not credited against each other.
For UK manufacturers who import carbon-intensive inputs and then export finished goods into the EU, a potential double exposure exists: UK CBAM on the imported inputs, and EU CBAM on the exported finished goods if those goods contain embedded carbon from non-UK origins. This double-payment risk is addressed in detail in the UK CBAM vs EU CBAM analysis.
Does UK CBAM Apply to Goods Imported From the EU?
UK CBAM applies to covered goods imported into Great Britain regardless of country of origin, including imports from EU member states. Goods produced in the EU are subject to EU ETS carbon pricing during production. Whether UK CBAM recognizes EU ETS carbon costs as a qualifying reduction against the UK CBAM charge depends on the UK government's recognition of the EU ETS as an equivalent scheme. As of April 2026, no formal equivalence decision has been announced.
Is There a De Minimis Threshold for UK CBAM?
UK CBAM is expected to include a minimum threshold below which the charge does not apply, similar to the EU CBAM de minimis of 50 tonnes annual mass per importer. The precise UK threshold has not been confirmed in legislation. UK importers near any anticipated threshold should model their position under both above- and below-threshold scenarios until secondary legislation is published.
What Records Must UK CBAM Importers Keep?
UK importers must retain supporting documentation for embedded carbon calculations, including supplier declarations, verified emissions reports, and any evidence of carbon pricing paid in the country of origin for at least 4 years after the relevant return date. This aligns with standard HMRC record-keeping requirements for customs and tax obligations.
Do CBAM Certificates Apply Under UK CBAM?
CBAM certificates do not apply under UK CBAM. The certificate mechanism is specific to EU CBAM. For detail on how EU certificates work, see CBAM certificates and CBAM declaration. UK importers do not need to open a CBAM Registry account or acquire EU certificates unless they also import covered goods directly into EU member states.
Can UK Importers Reduce Their UK CBAM Liability?
UK importers can reduce their UK CBAM tax charge in 2 ways: by providing verified actual embedded carbon data below the applicable default value, and by demonstrating that a qualifying carbon price was paid in the country of origin. The reduction for origin carbon pricing requires documentation showing the carbon price was legally binding, effectively paid, and applied to the specific goods imported. An authorized CBAM declarant operating in the EU uses the equivalent mechanism under EU CBAM Article 9.