The UK Carbon Border Adjustment Mechanism launches on 1 January 2027, placing a carbon tax on imports of steel, aluminium, cement, fertilisers and hydrogen. His Majesty's Revenue and Customs administers the mechanism, with first payments due by May 2028. Importers must register if their covered goods exceed fifty thousand pounds in value, assessed on both forward and backward-looking tests. Ongoing UK-European Union emissions trading scheme linking talks could save UK industry around eight hundred million pounds in European Union carbon border charges by 2030.