UK CBAM 2027: What Polish Steel and Aluminium Exporters Need to Do Now

From 1 January 2027, the United Kingdom will launch its own carbon border adjustment mechanism — UK CBAM (Carbon Border Adjustment Mechanism). Although the formal payer is the importer on the UK side, the Polish producer and exporter of steel and aluminium faces a real obligation: to gather, document and pass on verified data on embedded emissions. Without that data, its UK partner will fall back on the default (higher) emissions values set by HMRC — which will hit the price of the contract.

What UK CBAM is and who it affects on the Polish side

UK CBAM is a charge levied on importers in the United Kingdom on goods from high-emission sectors. The mechanism covers five product categories:

• iron and steel
• aluminium
• cement
• fertilisers
• hydrogen

Each sector is defined by specific 8-digit commodity codes. Aluminium scrap and steel scrap are excluded from the scope.

Who registers and pays in the UK: the importer — the entity in whose name the customs declaration is made in the UK. Registration is with HMRC. Threshold: £50,000 of CBAM import value within 30 days (a forward-looking test) or over the preceding 12 months (a backward-looking test).

The Polish exporter's role: the exporter does not register with HMRC and does not pay the charge. Its task is to supply the importer with verified data on embedded emissions. Without it, the importer applies HMRC's default values — usually higher than the actual emissions of modern mills, which means a higher CBAM charge and pricing pressure on the supplier.

Timeline: what and when

Note: Dates confirmed in HMRC documents on gov.uk (as of May 2026). The draft regulations were subject to a consultation that closed on 21 May 2026 — some details may still be refined.

Emissions data: what to prepare

The importer reports embedded emissions — the CO₂e emissions from producing the goods, per functional unit (e.g. per tonne of steel or aluminium).

Two options

Option A — actual data: the exporter supplies verified data for its own installation; the importer pays a charge that matches reality (often lower).

Option B — default values: no data = HMRC's default values, usually unfavourable for producers using modern technology.

What to gather and document

1. Energy consumption data — electricity, gas, coke, at installation/line level
2. Process data — emissions from processes (iron reduction, aluminium electrolysis)
3. System boundaries — which processes fall within scope (HMRC has published a draft System Boundaries Document)
4. Functional units — assigning the product to a unit (tonne of finished product, etc.)
5. Split between direct and indirect emissions — a methodology designed to be interoperable with EU CBAM

Verifying the data

The data must be verified by an accredited verifier. Standards: ISO 17029:2019 and ISO 14065:2020. The verifier must be independent and accredited. In Poland, accreditation is overseen by the Polish Centre for Accreditation (PCA). If you already take part in the EU ETS or EU CBAM, the same verifier can often handle UK CBAM too (the methodologies are designed to be interoperable).

Working with your UK customer

The UK importer will be the one to make first contact (it is the party answerable to HMRC). Expect enquiries in the second half of 2026.

Action plan for 2026

Step 1 — Check the CN codes of your products (now)

Identify which products exported to the UK fall within CBAM's scope. If in doubt, consult a customs agency or apply for a BTI (Binding Tariff Information) ruling.

Step 2 — Assess whether you can gather actual data (Q2–Q3 2026)

Do you have an energy and emissions monitoring system? Do you already take part in the EU ETS or EU CBAM? If so — you have a starting base. If not — start taking stock now.

Step 3 — Get in touch with a verifier (Q3 2026)

Book a pre-assessment. Verifiers' capacity will be limited in Q4 2026 and Q1 2027.

Step 4 — Contact your UK customer (Q3–Q4 2026)

Agree the format and deadline for the data. Offer to supply it before 1 January 2027.

Step 5 — Prepare the documentation (Q4 2026)

Emissions calculations, methodology, the verifier's report, correspondence — all in one place, ready on request.

Frequently asked questions (FAQ)

Does a Polish steel exporter need to register with HMRC? No. Registration applies to the UK importer, not the overseas producer.

What if I don't supply emissions data? The importer will use HMRC's default values — usually higher, meaning a higher charge and pricing pressure, or the loss of the contract.

Does data prepared for EU CBAM work for UK CBAM? Largely, yes — the methodologies are designed to be interoperable. Confirm the scope and units with your verifier.

When will the importer pay for the first time? The first period is 2027; the declaration and payment are due by 31 May 2028.

Is steel and aluminium scrap covered? No — scrap is excluded from the scope of UK CBAM.

How we can help

The customs agency agencjacelna.uk supports Polish steel and aluminium exporters with: checking CN codes, helping with communication with UK customers, coordinating with an emissions verifier, and handling export clearance on CDS. Get in touch with us before your customer starts asking questions.

Sources

• CBAM: Policy Summary — GOV.UK
• Draft regulations: CBAM (Emissions and Verification) — GOV.UK
• Introduction of a UK CBAM — GOV.UK