Ask where a consignment came from and the answer sounds obvious: it came from Rotterdam, or Shenzhen, or Chicago. In customs law that answer is usually wrong. Origin is not where goods were shipped from or bought from - it is where they were grown, produced or manufactured - and that legal origin is what decides whether a shipment pays full duty, a reduced rate, or nothing at all under a trade agreement.
Rules of origin exist to answer two questions: whether goods qualify for a tariff preference when imported, and whether a UK exporter can prove the origin their overseas customer needs to claim one. Every UK trade agreement, the Developing Countries Trading Scheme, and the non-preferential rules that apply everywhere else each carry their own origin rules, and preferential and non-preferential rules can both be relevant to the same goods. Where preferential rules do not apply, the non-preferential rules take over.
The stakes are concrete. Some products sit under preferential or non-preferential tariff quotas - a set quantity allowed in at a reduced or zero rate. The lower rate has to be claimed when the goods are imported, the trade tariff tool shows whether a quota exists and what documents a claim needs, and once the quota is exhausted, further imports pay the full rate. First come, first served is a customs principle as much as a queuing one.
Goods made from materials of a single country are treated as wholly obtained there: minerals extracted from its soil or seabed, live animals born and raised in it, products of hunting or fishing conducted there, and products made only from materials of the agreement country with nothing from anywhere else. Wheat milled in the country where it grew is easy. Almost nothing in a modern supply chain is that easy.
Most goods are made from materials of several countries, and they count as originating in a country only if the non-originating materials were sufficiently worked or processed there. Each trade agreement spells out what “sufficient” means, product by product, listing the classification heading or chapter, a description of the goods, and the processing that non-originating materials must undergo. Repacking, relabelling and simple assembly typically fail the test; substantial manufacturing typically passes.
If imported materials are not sufficiently worked in the UK, the origin stays with the last country where they were sufficiently worked - so a UK exporter cannot launder Chinese components into British origin by finishing and boxing them.
One common flavour of the sufficiency test is the ad-valorem rule: a ceiling on the value of non-originating materials, expressed as a percentage of the ex-works price of the finished product. The agreement will say, in effect, manufacture in which the value of all the materials used does not exceed X% of the ex-works price. Working it out means knowing the ex-works value - the price when the product left the factory, built from the materials and the other costs of manufacture, minus any internal taxes due or paid on export - and the production cost, including labour, profit, research and development and overheads. Businesses that cannot produce this arithmetic cannot sustain the preference claim.
Origin work belongs to the trader, but carriers see the consequences. A consignment declared with a preference it does not qualify for is a consignment that stops; a quota claimed after exhaustion is a duty bill nobody priced; an origin statement that does not match the goods is an audit finding. Operators moving goods under preference should know which of their customers claim preferences and on what basis - because when the claim fails at the frontier, it is the truck that waits.
The preference landscape is wider than the headline EU deal. The UK’s trade agreements each carry their own origin rules, and the Developing Countries Trading Scheme extends preferences to qualifying imports from developing countries under its own framework. Where preferential rules do not cover a movement - or the goods fail them - the non-preferential rules decide origin for everything else the system does: quotas, trade defence measures, marking and statistics.
Tariff quotas reward the organised. Because the reduced or zero rate inside a quota is finite and must be claimed at import, traders who check quota status in the trade tariff tool before shipping - and gather the supporting documents the claim requires - beat those who discover the quota was exhausted while their container was at sea. When a preferential or non-preferential quota is used up, the full rate of duty applies to everything after it, with no appeal to fairness.