HMRC has published an illustrative cement CBAM rate of £8.78 per tonne of CO2e ahead of the UK scheme’s 1 January 2027 start, plus a 313-page guide on emissions monitoring and verification.
HM Revenue & Customs (HMRC) published a worked example on 16 October that sets a cement CBAM rate of £8.78 per tonne of CO2 equivalent (tCO2e). The UK Carbon Border Adjustment Mechanism (CBAM) starts on 1 January 2027. The figures are the first cement numbers under the UK instrument.
What the example shows
Applied to HMRC’s default emissions values, the cement CBAM rate gives indicative charges of about £12.58 a tonne for imported clinker and £12.07 a tonne for non-white Portland cement. These charges come before any qualifying overseas carbon-price relief.
The calculation uses an average UK Emissions Trading Scheme (UK ETS) allowance price of £58.15 per tCO2e for July to September 2026. HMRC adjusts that price for domestic producers’ free allocation and its planned phase-out. The adjustment is what turns a carbon price into a border rate.
HMRC stresses that the numbers are illustrative. In its words, “these figures are illustrative, rather than forecasts or confirmed tax rates”. The rate for January to March 2027 will be published before the end of the year, and later rates will be updated quarterly.
A 313-page technical guide
HMRC also published a 313-page technical guide on emissions monitoring, reporting and verification. It is aimed at overseas producers, verifiers and UK importers. HMRC invites feedback on the guide until 13 November, and further updates are possible before implementation.
Producers that supply actual emissions data must appoint an independent accredited verifier whose scope covers the relevant production processes. Verification generally needs a physical site visit. The producer must then give the importer a report or a product-specific summary as evidence.
Accreditation bodies must publish lists of their CBAM-accredited verifiers and certificates. Importers can use default values instead of actual data. The choice has a catch. A return filed on default values “cannot subsequently be amended to substitute actual emissions data”.
What cement buyers and importers should check
The final cement CBAM rate could change as carbon prices move. It could also change when the UK ETS Authority finishes checking the free-allocation data behind the calculation. Importers planning for 2027 should read £8.78 as a guide, because HMRC will publish the January to March rate before the end of the year.
The gap between the clinker charge and the cement charge shows that product type affects the cost. Because default-based returns cannot be amended later, importers must decide between default and actual data at the point of filing.
Key dates
The timetable is short. HMRC published the worked example on 16 October and invites feedback on the technical guide until 13 November. It will publish the rate for January to March 2027 before the end of the year. The scheme starts on 1 January 2027, and HMRC will update the rate each quarter after that.
Each of those dates gives cement importers and overseas producers a decision point. The consultation window closes first, the first applicable rate follows, and the charge begins on the first day of 2027. Producers that want to supply actual data need time to appoint an accredited verifier and arrange a site visit, so the consultation window is also a practical planning deadline.
Overseas producers face a practical task. They need a verifier with the right scope and a site visit, and they need to produce a report that importers can rely on. The 13 November feedback window is the chance to raise problems with that process before the scheme starts.
Earlier coverage explains the compliance side in more detail. See the report on new UK CBAM compliance requirements and the note on EU verification guidance and amended default values. Both pieces describe how default and verified emissions data are handled.
For the cement sector, the first UK figures turn a policy design into a number. At £8.78 per tCO2e, the cement CBAM rate gives UK producers and importers a reference point for planning, with the caveat that HMRC calls every figure illustrative.
