Rules changelog
Every change to the UK CBAM rules, dated, in plain English.
We watch the primary sources (legislation.gov.uk, the gov.uk CBAM collections, HMRC guidance) twice a week and verify every movement against the source document before it appears here. Account owners receive each entry by email with what it changes in their numbers. Last reviewed 2026-09-29.
2026-09-29
Scenario rate moved to the Q3 2026 auction average: £58.15 per tonne of CO2e
No official CBAM rate exists yet, so every indicative figure in CBAMReturn is priced at a labelled scenario rate. Until today that was £49.25, the average UK ETS auction clearing price for April to June 2026. The July to September auctions are now complete and averaged £58.15, so the scenario has moved to that figure. This mirrors how the real rate will work: under the rate regulations (S.I. 2026/809) each quarter's rate starts from the previous quarter's average auction price and is then reduced to reflect the free allowances UK producers still receive. That reduction is not yet published, so the scenario applies none, and the real rate will be lower than the auction average it starts from. The first real rate, for January to March 2027, will be set by the October to December 2026 auctions. HMRC's illustrative rate is still promised for this autumn; when it lands, every figure moves to it.
What it changes for youEvery indicative liability rises by about 18% before any carbon price relief. Nothing else changes: the threshold test, your supplier data and your records are unaffected. Saved ledgers and positions were re-priced on 29 September, and every line in your position shows the rate it used.
2026-09-09
Emissions and verification regulations made: how supplier data is measured, verified and reported is now law
The Carbon Border Adjustment Mechanism (Emissions and Verification) Regulations 2026 (S.I. 2026/995) were made on 8 September and laid on 9 September, in force 1 January 2027. They fix how embodied emissions are calculated (default value times weight, or an eight-step actual-emissions method from verified installation data), the monitoring period (for 2027 imports, the most recent verified year of 2026 or 2027, or the year of production; from 2028 the two preceding years), who may verify (independent of importer, installation and precursor producers, and accredited by a full member of the Global Accreditation Cooperation), the conversion factors for nitrous oxide and the aluminium PFCs, and a six-year duty to keep the verification report. They also amend the July administration regulations: from 1 January 2027 every return must state, per good, the default value level used or the verified emissions intensity, and whether a UK-produced precursor was used; and records must note where returned-goods relief applies. A separate order applies late-payment and repayment interest to CBAM from 1 January 2027. Materiality (5%) and the ISO standards for verifiers and accreditation bodies sit in the accompanying force-of-law notice, published in draft-final form the same day; the word 'draft' is removed on 1 January 2027. Still to come: the default values notice, the first illustrative rate (promised for autumn), and HMRC's registration service (by 1 January 2028).
What it changes for youYour return preview now shows the emissions basis per commodity code exactly as the amended return will require: the default value level, or the verified intensity and verifier. Supplier data from calendar year 2026 can serve 2027 imports if it is the most recent verified year, so a supplier's 2026 verification is worth chasing now. The verifier record on the Suppliers page (accreditation body and number, independence) matches what the regulations and the verification report must show.
2026-09-04
September check: no change to the rules; still awaited are the emissions regulations, the illustrative rate and default values
A full re-verification against every primary source found no change to any load-bearing fact since July. Still outstanding: the emissions and verification regulations (draft; consultation closed, no outcome published), HMRC's promised illustrative CBAM rate (autumn 2026), the default values notice, and the Commissioners' notice on additional return contents. On the UK to EU side, negotiations on linking the two emissions trading systems are open and no agreement has been concluded: EU-origin goods remain in scope for UK CBAM.
What it changes for youNothing changes in your numbers. Emissions continue to use the labelled proxy default values and the scenario rate; both re-price automatically when HMRC publishes the real ones, and you will receive one of these emails when they do.
2026-08-27
HMRC publishes the official list of qualifying carbon pricing schemes
Sixteen overseas schemes are recognised for carbon price relief as of the 19 June 2026 assessment date, including the EU ETS, China's national ETS, India's CCTS, the Swiss ETS, Korea's K-ETS and the carbon taxes of Singapore, South Africa and Chile. The list is provisional and non-exhaustive: a scheme that meets the criteria can still qualify with evidence, and listed schemes can drop out. Relief equals the effective price actually paid (after free allowances, rebates and thresholds are netted off) times the embodied emissions, capped at the CBAM liability, evidenced by a verifier-completed form.
What it changes for youIf a supplier's installation pays a price under one of these schemes, record it in the relief workspace against that supplier; the position applies it per line, capped at the charge, and the return preview shows it.
2026-07-16
HMRC: registration opens by 1 January 2028; year one is a record-keeping year
HMRC's first guidance wave (13 to 16 July 2026) says the CBAM registration service will open by 1 January 2028 and instructs businesses that cross the threshold during 2027 to keep records so they can register and file when the service is available. The guidance sets out which imports do not count toward the threshold (private use; returned goods within three years, unaltered; temporary admission with full relief; special-procedure goods until discharged), the registration particulars (EORI, VAT number, trigger date, estimated 12-month weights by sector), the six-year record-keeping rule, and the carbon pricing verification form a verifier completes for relief.
What it changes for youYou can now mark individual lines as disregarded (with the reason) on the position page, and the organisation profile holds the registration particulars so the pack is ready the day the service opens.
2026-07-14
Core CBAM regulations made: deadlines, return contents and the rate formula are now statutory
Three statutory instruments were made on 13 and 14 July 2026, all in force 1 January 2027. S.I. 2026/830 fixes the timetable: anyone crossing the threshold during 2027 has until 31 January 2028 to register; the whole of 2027 is one accounting period with return and payment due 31 May 2028; then quarterly (31 July 2028, 29 September 2028, then the last working day of the second month after each quarter). S.I. 2026/802 sets what a return contains per 8-digit commodity code (weight, carbon price relief, place of origin, a truth declaration) and requires records evidencing each good's place of origin, kept six years. S.I. 2026/809 fixes the rate mechanics (mean UK ETS auction price of the preceding quarter, adjusted for free allocation) and carbon price relief (effective overseas price, capped at the liability).
What it changes for youYour position now shows a return preview shaped exactly as the regulations describe, per commodity code, and flags lines with no place of origin. The registration deadline shown on triggered positions uses the 2027 easement (31 January 2028).
2026-03-18
UK CBAM becomes law: Finance Act 2026 receives Royal Assent
Part 5 of the Finance Act 2026 (sections 142 to 158 and Schedules 16 to 19) enacts the UK Carbon Border Adjustment Mechanism. From 1 January 2027, importers of iron and steel, aluminium, cement, fertiliser and hydrogen pay a charge on the emissions embodied in those goods. The £50,000 registration threshold (rolling 12 months, tested on the first of each month, plus a 30-day forward test) is in the Act. The liable person is the importer: the person completing the customs declaration or on whose behalf it is made.
What it changes for youNothing to file yet. The clock on data collection starts 1 January 2027: the first return (May 2028) is built from 2027 data and a return filed on default values cannot later be amended to actual supplier data.
The full evidence trail — every source, pinned and dated — sits behind the guides. Something moved that isn't here yet? hello@cbamreturn.co.uk.