The UK’s Carbon Border Adjustment Mechanism (CBAM) is due to take effect on 1 January 2027, covering specified imports of iron and steel, aluminium, cement, fertiliser and hydrogen. For businesses, the £50,000 registration threshold is an early planning test: it determines when an importer must register, but it is not a tax-free allowance.
How The £50,000 Threshold Works
An importer must assess the total value of its in-scope goods against two tests. The forward-looking test asks whether it expects to import at least £50,000 of CBAM goods over the next 30 days. The monthly test checks whether it imported at least that amount during the previous 12 months. In 2027, the look-back begins on 1 January, and imports made before that date do not count.
The value used is the value applied, or that would apply, for customs-duty purposes. Goods across the covered sectors count toward the same threshold for the liable importer. The responsible party is generally the person named on the customs declaration, or the person on whose behalf it is made.
Reaching the threshold can bring record-keeping and reporting obligations even if the business’s eventual CBAM charge is reduced by a qualifying carbon price already paid overseas. Some goods, including certain private-use imports, UK-origin goods and goods covered by specified customs reliefs, may not count toward the threshold.
What Businesses Should Prepare
Before 2027, importers can identify which commodity codes they use, determine who is legally responsible for each shipment and build a process to track the relevant customs values. Forecasting the next 30 days will matter alongside monthly reviews of imports: a business could meet the forward-looking test before its past shipments reach £50,000.
The timing of registration adds another step. Although CBAM liability begins in 2027, registration is scheduled to open on 1 January 2028. Businesses that become liable during 2027 will have until 31 January 2028 to register, and must retain relevant import records in the meantime. The first CBAM accounting period covers 2027, with returns and payments due by 31 May 2028.
MarketMind Insight
The threshold makes customs data and supply-chain visibility central to CBAM readiness. Businesses that import covered materials should map shipments to the liable importer, track customs values across sectors and set alerts for both the 30-day forecast and monthly look-back. The key date is not simply when annual imports pass £50,000; it is the first day either test is met.
