Who decides when import duty falls to zero

The Treasury made a customs regulation on 2 November 2026 that will change import-duty treatment for steel inputs, kerosene, fertilisers and some agricultural and food goods from 26 November 2026, according to the statutory instrument. The important question is not only which goods get cheaper to import; it is who had the power to make that happen.

Here is the short version. Parliament built the machine in the Taxation (Cross-border Trade) Act 2018. The Treasury then used that machine to make the regulation. The instrument says the Treasury had regard to a recommendation from a Secretary of State. HMRC and the Department for Business, Innovation, Science and Trade hold the reference documents that contain the detailed lists. If you want to know whether a real shipment gets the lower rate, you may need those documents, not only the regulation itself.

A tariff is a tax on an imported good. If a business brings a product into the UK, customs law asks what the product is, where it comes from, and which commodity code applies. A commodity code is the numbered category used to classify goods. Steel for making linepipe has a different legal treatment from finished steel pipe, just as flour can be treated differently from a cake.

The power begins with Parliament. The 2018 Act tells the Treasury to establish and maintain the UK customs tariff, meaning the system that classifies goods, gives them codes and sets import-duty rates. Section 12 of that Act allows tariff suspensions, which are reduced or removed duties for specified goods. Section 19 allows reliefs from import duty. Schedule 2 paragraph 13 defines goods declared for an authorised-use procedure as goods that are to be put to a use specified in regulations.

That is the first decision: Parliament decided not to put every future tariff rate in an Act of Parliament. Instead, it gave ministers power to alter the tariff through regulations and linked documents. That is common in tax and customs law because the list of goods is long and changes often. It also means the working detail can be hard to see unless you know where to look.

The next decision is made by the Treasury. The Customs (Tariff and Miscellaneous Amendments) (No. 7) Regulations 2026 were made by the Treasury on 2 November 2026, laid before the House of Commons on 3 November 2026 and come into force on 26 November 2026, according to the instrument. They were signed by Christian Wakeford and Jade Botterill as two Lords Commissioners of His Majesty’s Treasury.

The regulation does not print the full new tariff table in its main text. It changes three earlier sets of regulations by replacing references to older documents with references to newer ones. For authorised uses, it replaces HMRC’s eligible-goods-and-uses document version 2.26 dated 1 September 2026 with version 2.27 dated 27 October 2026, according to regulation 2. For authorised-use rates, it replaces version 1.26 dated 1 September 2026 with version 1.27 dated 27 October 2026, according to regulation 3. For tariff suspensions, it replaces the tariff suspension document with version 3.8 dated 27 October 2026, according to regulation 4.

This is where the story becomes less visible. The explanatory note says the new authorised-use documents reduce import duty on nine commodity codes for steel goods used to make bright bar and wire, and on six commodity codes for steel goods used to make linepipe. That makes fifteen steel commodity codes in total, according to the explanatory note. It also says the tariff suspension document inserts new suspensions to 0% for kerosene, fertilisers and various agricultural and food goods, with each new suspension excluding goods originating from Russia or Belarus.

But the explanatory note does not list the fifteen steel commodity codes. It does not give the old rates. It does not give the new rates for each steel code. It does not list every kerosene, fertiliser, agricultural or food code. It does not state the value of imports affected, the expected revenue lost by the Exchequer, or whether the saving is likely to reach consumers. To find the operative detail, you must go to the incorporated documents named in the regulation.

That phrase matters: incorporated documents. It means a document outside the statutory instrument is made legally important because the regulation points to it. The law is not only on the page you first open. It is also in the document the page adopts.

Now for the hiding word: authorised use. It sounds like a small administrative label. It is not. Authorised use is a customs special procedure. It gives lower duty only if the goods are used for the specified purpose and the importer or user can meet the conditions. The relevant documents set out the goods, uses and rates, while the regulation itself makes those documents part of the operative framework.

So a lower authorised-use rate is not the same as a general tariff cut. If steel is imported under authorised use to make linepipe, the relief depends on proving that the steel went into that permitted use. If it is diverted, the applicable customs rules may require the avoided duty to be paid. In plain terms, the importer may have to pay the duty it avoided.

This explains who benefits and who pays. The direct beneficiaries are importers and manufacturers able to use the listed steel inputs for bright bar, wire and linepipe and comply with authorised-use rules. Importers of the newly listed kerosene, fertiliser, agricultural and food goods also benefit from a 0% suspended rate if the goods do not originate in Russia or Belarus. The Exchequer pays through customs revenue not collected, but the instrument gives no amount. UK producers may pay if lower-duty imports undercut them, but the instrument gives no assessment of that risk. Businesses using authorised-use relief pay in paperwork, record-keeping and compliance, but the instrument gives no quantified cost.

The regulation says no full impact assessment has been produced because no, or no significant, impact on the private, voluntary or public sector is foreseen. That is an official conclusion, not an explanation. The instrument changes duty treatment across steel, heating oil, fertiliser and food-related imports, yet it does not show the calculation behind the no-significant-impact view.

The regulation also says it maintains the position of existing legislation covered by a Tax Information and Impact Note published on 13 January 2021. That note was about the UK’s Integrated Tariff Schedule after the post-Brexit customs system began. It can explain the framework. It cannot, by itself, prove the impact of these particular additions dated 27 October 2026.

So who decides that an imported good is taxed at zero? Parliament decides the structure and gives ministers the tools. The Secretary of State recommends. The Treasury makes the regulation. HMRC and DBIST publish the documents that hold the itemised legal detail. The applicable customs rules determine whether an importer claiming authorised use has done what it said it would do.

The official account tells you this is a technical tariff update. Sometimes technical updates are exactly that. But technical does not mean unimportant. It often means the decision has been moved into a place where only specialists know to look.

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