Twelve weeks to UK CBAM: what importers still do not know
The UK CBAM starts on 1 January 2027. The legislation is in place, as we reported when the emissions and verification regulations were laid in September. What importers still lack is the set of numbers that turns the rules into a cost. This is the position with twelve weeks to go.
One detail worth knowing: 2026 data counts
The final Emissions and Verification Regulations (SI 2026/995) differ from the spring draft on which year's data an importer may use. Under regulation 9, for goods imported before 1 January 2028 the monitoring period is the most recent calendar year with verified emissions data, taken from the year of import or the year before. Verified 2026 data can therefore support 2027 imports. The alternative is to use data from the calendar year in which the goods were produced. From 2028, the rule becomes the most recent verified year from the two calendar years before import.
This matters because verification of a calendar year can only start once the year has ended, and the first return and payment, covering the whole of 2027, are due by 31 May 2028. A supplier already producing verified data for 2026, for example for EU customers, has a head start that UK importers can use.
Two smaller points come from the same instrument. Verifiers must be accredited by a body that is a full member of the Global Accreditation Cooperation (regulation 15), and returns must state either the default value used or the verified emissions intensity (regulation 17).
The numbers still missing
HMRC has said it will publish an illustrative CBAM rate this autumn. An HMRC official told Carbon Pulse in late September that the trial rate will follow the final methodology with preliminary inputs, and is meant for planning. The sector figures for free allocation that feed into the rate have not been confirmed, and consultancy estimates suggest small changes in them move the rate a long way.
Default emissions values have not been published either. They are due before the start date and are expected to be a single value for each product, whatever its country of origin, where the EU sets values by product and country. If so, a UK importer's choice of origin will not change the default, and the gain from verified data will be largest for the cleanest producers.
Free allocation and the EU link
The UK ETS Authority plans to phase out free allowances for CBAM sectors over nine years from 2027, mirroring the EU's original schedule. A government official said in September that a decision on the benchmarks to be used from 2028 will come shortly, and a consultation on how the phase-out applies to hydrogen closed on 2 October. The EU has since proposed slowing its own phase-out to 2038, so the two schedules may diverge.
On linking the UK and EU carbon markets, the leaders' summit expected this summer was delayed by the change of Prime Minister and may now take place in November. Until a link is legally in force, both schemes apply in full. One consequence, raised by compliance advisers, is that goods imported into the EU and then shipped on to the UK can be charged at both borders, because CBAM paid in the EU is not a carbon price that qualifies for UK relief.
What to do now
Ask suppliers whether they will have verified 2026 data, and who their verifier is. Build the 2027 budget as a range until the illustrative rate appears, then update it. Check any goods that reach you through the EU for exposure at both borders. Trade bodies including the Aluminium Federation have asked the government for a clearer implementation roadmap, and the rate and default values are both expected this autumn, so plan to revisit your numbers before Christmas.
CBAM-Assured provides UK CBAM training and MRV support for importers and their overseas suppliers; contact us to be ready for January.