UK CBAM Consultations 2023-2026: Every Round and What Changed

Five UK CBAM consultation rounds ran between March 30, 2023 and May 21, 2026, and three of them ended with a published government response that set or changed the design. The UK carbon border adjustment mechanism is a tax, charged by HMRC from January 1, 2027, and its sector list, registration threshold, emissions scope and return timetable were each settled in a named round. Which round fixed which rule?

This record answers that question with dates and documents taken from gov.uk and legislation.gov.uk, last checked on October 12, 2026.

General Summary

The UK CBAM consultation record consists of one exploratory consultation (2023), one policy design consultation (2024) and three technical consultations on draft legislation (one in 2025, two in 2026). The government received over 160 responses in 2023, over 340 in 2024 and over 70 in 2025.

The two policy rounds produced the largest changes: seven sectors became five, and the registration threshold rose from £10,000 to £50,000. The three technical rounds tested drafting.

Which Consultations Shaped UK CBAM?

Five consultations shaped UK CBAM, and the March 2024 policy design consultation shaped it most: its response fixed the sectors, the registration threshold and the tax administration model. HM Treasury published the two policy rounds jointly, first with the Department for Energy Security and Net Zero and then with HMRC. HMRC alone published the three technical rounds.

The three types of round did different jobs, listed below.

• Exploratory (2023): asked whether the UK needed a carbon border adjustment mechanism at all, alongside product standards and emissions reporting.
• Policy design (2024): asked 41 numbered questions on scope, liability calculation and administration.
• Technical (2025 and 2026): asked whether draft legislation delivered policy already decided. The 2025 page stated: "It is not a further consultation on the policy design."

Each round feeds a rule explained in the UK CBAM guide, from liability to returns. The separate European mechanism, which was not part of any of these rounds, is covered in the EU CBAM guide.

The UK CBAM Consultation Record

The UK CBAM consultation record runs from March 30, 2023 to May 21, 2026, and gov.uk documents every round. The table lists the five rounds in date order.

One sourcing note applies to the 2025 row. The original gov.uk address was re-checked on October 12, 2026 and still redirects to the February 2026 consultation, as it has since February 10, 2026. The opening and closing times (9:30am on April 24, 2025 to 11:59pm on July 3, 2025), the response count and the outcome text therefore come from Internet Archive copies of the consultation page (captured December 16, 2025) and of its outcome document (captured November 26, 2025).

Live documents confirm the round but date it loosely. HMRC's tax information and impact note and the memoranda to SI 2026/802 and SI 2026/809 place it between March and July 2025. The memorandum to SI 2026/995 says April to July 2025.

The instruments these rounds produced are set out in the UK CBAM legislation guide.

The 2023 Carbon Leakage Consultation

The 2023 consultation asked whether a CBAM was the right tool against carbon leakage. The response of December 18, 2023 committed to a mechanism "by 2027" covering aluminium, cement, ceramics, fertiliser, glass, hydrogen, and iron and steel.

The accompanying factsheet fixed the tax model in one sentence: "This system will not involve the purchase or trading of emissions certificates." The same response said the government "does not intend to implement" mandatory product standards for any specific sector at that point and would pursue voluntary product standards first.

The 2024 Policy Design Consultation

The 2024 consultation ran for 12 weeks and proposed the working parts of the tax. Its proposals included a £10,000 registration threshold, a backward-looking test applied daily, commodity codes across seven sectors, a single default value per product, and quarterly accounting periods from 2028 with returns due one month later.

Over 340 written responses arrived, 122 of them from international or overseas respondents. Trade associations formed the largest group, followed by UK importers, manufacturers and academia.

The Government Response

The government response of October 30, 2024 confirmed the January 1, 2027 start and changed three proposals. It removed glass and ceramics, raised the threshold ("the government has decided to increase the value of the threshold to £50,000") and moved the backward-looking test from daily to monthly.

It kept four proposals unchanged: the exclusion of aluminium and iron and steel scrap, a single default value per product, a quarterly rate per sector, and recognition of explicit overseas carbon prices only. It deferred two: the free allocation adjustment and the return window from 2028.

The 2025 Draft Legislation Consultation

The 2025 round published the draft primary legislation together with a policy update. That update settled the deferred return window: quarterly accounting periods from January 1, 2028, with a two-month return and payment window. HMRC received over 70 responses, and the outcome document of November 26, 2025 listed the six technical changes below.

1. The free allowance adjustment in the rate uses a sectoral average of emissions covered by free allowances over a baseline period, adjusted annually.
2. Carbon price relief extends to carbon prices incurred under other carbon border adjustment mechanisms.
3. Emissions embodied in UK-produced precursor goods inside a complex imported good are exempt.
4. Goods under temporary admission with full relief from customs duty are exempt.
5. Repayment claims for overpaid CBAM carry a three-year time limit.
6. The group treatment provision was removed.

The same document recorded the Budget 2025 decision that indirect emissions stay out of scope at launch. Its wording: "Their inclusion in CBAM scope will be delayed until 2029 at the earliest." The stated reason is continued support for the Energy Intensive Industries Compensation Scheme. HM Treasury's live factsheet, updated November 28, 2025, repeats the commitment.

The legislation then entered the Finance Bill 2025 to 2026 and became Part 5 of the Finance Act 2026, which received Royal Assent on March 18, 2026.

The 2026 Draft Regulations Consultations

The two 2026 rounds each ran for six weeks and tested the statutory instruments. Neither consultation page carries a response document as of October 12, 2026: both still read "We are analysing your feedback". The outcome is recorded instead in the explanatory memoranda to SI 2026/802, SI 2026/809 and SI 2026/995 on legislation.gov.uk. Legislation.gov.uk shows no memorandum for SI 2026/830.

Each of the three memoranda gives the same verdict: "The overall consensus from the consultation responses was that the instrument met the policy intent." SI 2026/809 gained a definition of "tonne" and a clarification that a scheme can qualify for carbon price relief even where it does not impose a cost in all instances.

SI 2026/995 gained a definition of "operator" and a simpler record-keeping rule. It also now lets importers of goods arriving in 2027 use verified emissions data from calendar year 2026.

Two things sit outside these rounds. The fifth CBAM instrument, SI 2026/994 (the interest appointed day order, made September 8, 2026), was not part of either consultation. And the force of law notices are still drafts: HMRC published the draft administrative and carbon price relief notice in July 2026 and the draft Emissions and Verification notice on September 9, 2026, replacing its file on October 9, 2026. Neither has legal force before January 1, 2027.

What Changed Between Consultation and Final Design

Nine design decisions moved between a consultation proposal and the final rules, and the registration threshold moved furthest: from £10,000 to £50,000. The table maps each decision to the round that settled it.

The threshold change shows how a submission position became a rule. Around a quarter of the respondents who answered the question argued that £10,000 was too low, citing administrative burdens for small businesses. The government's updated modelling then estimated that £50,000 keeps over 99% of imported emissions in scope while removing over 80% of otherwise registrable businesses.

Three of these outcomes now sit in Part 5 of the Finance Act 2026. Section 143(3) lists the five kinds of goods: aluminium goods, cement, fertilisers, hydrogen, and iron and steel goods. Paragraph 2 of Schedule 17 sets the £50,000 threshold and applies the backward-looking test on the first day of each month. Section 158(1) applies the tax to goods imported on or after January 1, 2027.

What Remains Open After the Consultation Rounds

Five design questions remain open as of October 12, 2026: glass and ceramics, indirect emissions, the default value method after 2027, refined products, and exemption for goods from a linked emissions trading scheme. The government has stated a position on each without a final decision.

The October 2024 response said products at risk of carbon leakage in the glass and ceramics sectors "will be considered for inclusion at a later date". Indirect emissions are delayed until 2029 at the earliest. On default values, HM Treasury's factsheet, updated November 28, 2025, says: "Post-2027, the government is considering the viability of moving to an alternative approach for default emissions values." The April 2025 policy update, now available only in archived form, used "feasibility" in the same sentence. The UK CBAM default values page tracks the Treasury notice that will set the 2027 figures.

On refined products, the November 2025 outcome said the government is considering the feasibility and impacts of including them in future. On linkage, section 156 of the Finance Act 2026 gives a power to exempt goods from a linked scheme, and HMRC's policy summary, updated September 9, 2026, states: "There are currently no jurisdictions exempt from CBAM."

Issues Industry Raised That Were Not Resolved

Six positions raised in the 2024 submissions were not adopted. Annex A of the response, its list of stakeholders consulted, includes UK Steel, the Mineral Products Association, Make UK, British Glass and Ceramics UK. The response does not attribute positions by name.

• Exports: respondents said a CBAM does not address carbon leakage in export markets and suggested a refund of the UK carbon price on exported goods. The response adopted no such mechanism.
• More than one rate per sector: the steel industry suggested three rates for steel. The design has a single rate per sector.
• Country-specific default values: requested as protection against under-pricing. A change of approach has not been confirmed.
• Downstream products: inclusion "would add disproportionate burdens and is not currently feasible".
• Direct reporting to HMRC by overseas installations: rejected. Importers must hold the verified data themselves.
• Exemptions for developing countries: suggested alongside technical assistance. The policy summary lists no exemption based on development status.

Is Another UK CBAM Consultation Expected?

No UK CBAM consultation is open on October 12, 2026, and none has been announced. HMRC's CBAM collection on gov.uk lists only closed rounds, and a gov.uk search for open consultations and calls for evidence on CBAM returned no results that day. The government has said it will keep sectoral and product scope under review beyond 2027.

At Budget 2025 the government also said it would publish a call for evidence on the fuel sector. The nearest match on gov.uk is the energy department's call for evidence "Future of the UK downstream oil sector", open from February 23 to April 20, 2026. That document does not mention CBAM. No decision on refined products in CBAM has been published as of October 12, 2026.

The site's paid email service, CBAM Brief (EUR 199 a month), sends an alert the day a CBAM certificate price, default value, CN code or deadline changes.

Frequently Asked Questions About UK CBAM Consultations

How many UK CBAM consultations have there been?

Five. One exploratory consultation ran in 2023, one policy design consultation in 2024, and three technical consultations on draft legislation in 2025 and 2026. All five are closed.

When did the last UK CBAM consultation close?

The most recent UK CBAM consultation closed at 11:59pm on May 21, 2026. It covered the draft Emissions and Verification Regulations, which were made as SI 2026/995 on September 8, 2026 and come into force on January 1, 2027.

Where is the UK CBAM consultation response?

Three responses were published: December 18, 2023, October 30, 2024 and November 26, 2025. The first two sit on their gov.uk consultation pages, and the 2025 outcome page now redirects. For the two 2026 consultations, HMRC has not published a response document on the consultation pages as of October 12, 2026. The explanatory memoranda to SI 2026/802, SI 2026/809 and SI 2026/995 summarise those outcomes.

Which sectors did the UK CBAM consultations remove?

Glass and ceramics. Both were named in December 2023 and removed by the October 2024 response, which found them, on average, less emissions intensive than the five sectors that remain. Product coverage is set out in the UK CBAM sectors guide.

Did the consultations change how the UK CBAM rate is set?

Partly. The quarterly rate per sector survived every round. The free allocation adjustment inside it changed in November 2025 to a sectoral average over a baseline period. The UK CBAM rate guide explains the resulting formula in SI 2026/809.

How does the UK process compare with changes to EU CBAM?

The UK settled its design through consultation responses before the tax starts on January 1, 2027. The EU changed its mechanism after its transitional phase had begun, through amending legislation, Regulation (EU) 2025/2083, covered in the CBAM omnibus guide.