The United Kingdom plans to implement its carbon border mechanism through a tax-based system, rather than the certificate-trading model used by the European Union, as companies supplying steel to both markets prepare for separate compliance requirements.
The UK mechanism is scheduled to begin on 1 January 2027 and will cover specified goods in iron and steel, aluminium, cement, fertilisers and hydrogen. Its initial design focuses on direct emissions, with the resulting liability collected through the tax system.
A UK government official told Carbon Pulse that the model is intended to simplify administration and incorporate lessons from the EU mechanism. The different architecture means, however, that UK and EU obligations will remain separate rather than interchangeable.
Registration and payment requirements set for 2027 imports
HM Revenue & Customs has established a £50,000 registration threshold for relevant imports under its prescribed tests. The first accounting period will cover 2027, while the initial return and payment will be due by 31 May 2028.
The timing creates a period between the arrival of covered goods and settlement of the UK carbon border liability. Businesses importing steel and other covered products will therefore need to account for the tax when establishing commercial arrangements for 2027.
UK rates are designed to reflect the effective carbon costs incurred by domestic producers, including the UK Emissions Trading Scheme and free allocation. Importers will be able to rely on qualifying actual emissions data or applicable default values when determining their liability.
UK carbon tax will operate separately from EU CBAM
The UK system will not require importers to purchase EU-style CBAM certificates for their UK obligations. The EU certificate price therefore cannot be used to derive a single equivalent UK tax rate for steel.
For businesses distributing products into both jurisdictions, administrative requirements remain distinct. Companies will need to map product classification, liable importer identity, emissions evidence and return deadlines separately for UK and EU trade.
The distinction is particularly relevant to distributors holding stock destined for both markets. Although the UK’s tax structure may simplify its own administration, it does not create a common compliance framework covering both jurisdictions.
Contract terms face carbon-cost allocation decisions
The interval between imports and the first UK payment deadline also affects commercial contracts. A seller agreeing a 2027 price before the final tax liability is calculated will need to establish whether the agreed price incorporates the carbon border charge or allows for a subsequent adjustment.
The UK approach consequently changes the mechanism through which the border carbon cost is collected, but companies will still need to establish which goods are covered, which emissions are relevant and which contractual arrangements determine responsibility for the resulting tax liability.
