If you import carbon-intensive goods into the UK, new tax rules start on 1 January 2027. HM Revenue & Customs (HMRC) has issued fresh guidance ahead of the launch. It gives importers clearer instructions on emissions data, tax rates and reporting.
On 16 October 2026, HMRC published default emissions values and updated its guidance on carbon calculations.
The changes are part of the UK’s Carbon Border Adjustment Mechanism (CBAM). The tax aims to make sure imported goods carry carbon costs similar to those UK manufacturers pay.
What Has HMRC Updated for UK CBAM in 2027?
HMRC’s latest guidance shows importers how to work out the carbon emissions linked to their goods.
You can use verified emissions data from overseas manufacturers. If you can’t get it, you can use HMRC’s published default values. But default values may push your tax bill up. HMRC also warns that once you submit a return, you can’t swap default values for actual emissions data.
The new CBAM rates guidance confirms that rates will change every quarter. They will follow carbon prices under the UK Emissions Trading Scheme (UK ETS).
Which UK Businesses Will CBAM Affect?
The tax covers certain imported goods in five sectors:
- Aluminium
- Cement
- Fertilisers
- Hydrogen
- Iron and steel
Check your product commodity codes to see if your imports fall within scope.
For now, CBAM covers direct emissions from production only. Indirect emissions, such as those from electricity use, stay out until 2029 at the earliest.
What Is the £50,000 CBAM Registration Threshold?
You must register when you meet either of two tests.
The first applies if you expect to import £50,000 or more of CBAM goods in the next 30 days. The second looks at whether your imports reached £50,000 over the previous 12 months. For 2027, only imports from 1 January count.
Registration isn’t open yet, but you should still track these thresholds from the start.
When Are the First CBAM Returns and Payments Due?
The tax starts on 1 January 2027, but the first payment comes later.
If you become liable during 2027, you generally have until 31 January 2028 to register. HMRC’s registration service is expected to open on 1 January 2028.
Your first CBAM return covers the whole of 2027. You must file it and pay by 31 May 2028. From 2028, reporting moves to quarterly periods.
If you don’t prepare, you could face surprise tax costs, wrong returns or penalties for missed duties.
What Should UK Importers Do Before January 2027?
If you import affected goods, start getting ready now:
- Review your customs records and commodity codes, along with your post-Brexit import VAT position
- Check if your expected imports will pass the £50,000 threshold
- Ask overseas suppliers for verified emissions data
- Compare actual emissions figures with HMRC’s default values
- Keep accurate records of imports, emissions and carbon costs through reliable bookkeeping
- Plan for future CBAM payments and reporting deadlines with a solid cash flow forecast
Starting early helps you avoid errors and unexpected costs.
How Can Lanop Help Businesses Prepare for UK CBAM?
HMRC’s latest guidance makes the rules clearer, but compliance still takes careful planning.
At Lanop Business & Tax Advisors, we have experience in tax compliance, accounting and cross-border business advice. We can help importers review their financial records, understand registration duties and get ready for new reporting requirements.
Don’t wait until your first CBAM payment is due to check your exposure. Contact Lanop to talk about your tax planning and compliance needs before January 2027.
