The UK has added the piece that says how emissions get measured. On 8 September 2026 the Treasury and HMRC made SI 2026/995, the Carbon Border Adjustment Mechanism (Emissions and Verification) Regulations 2026. They were laid before the Commons on 9 September and come into force on 1 January 2027, the day UK CBAM starts.
It sits alongside the two instruments from July: SI 2026/809 (how the rate is calculated, and carbon price relief) and SI 2026/802 (registration, returns and records). We covered those in UK CBAM moves into law.
What SI 2026/995 sets
- Two ways to count embodied emissions. Either the default values the Treasury publishes by notice, or actual emissions built from verified installation data, converted to CO₂ equivalent and turned into an intensity per tonne of goods.
- System boundaries.Which emissions and processes count for each good follow HMRC's System Boundaries Document (version 1.00, 10 July 2026), which the Regulations now reference.
- Annual monitoring and independent verification. Operators monitor each year; verifiers must be independent and accredited, and HMRC can publish detailed notices on methodology, verification and accreditation.
- Records. Registered importers keep verification reports for six years after the accounting period.
What it does not set: the numbers
SI 2026/995 contains no default values and no CBAM rates. It says defaults will come by Treasury notice, and that notice has not appeared yet. Until it does, anyone planning to rely on UK defaults cannot price a UK CBAM bill. If your suppliers can give you verified actual emissions, this is the rulebook that data will be checked against, so it is worth asking them now. The supplier data templates cover the request.
When the UK defaults land, they land here. The UK CBAM overview tracks the rules and the threshold checker tells you whether you are in scope at all.