The UK has now concluded free trade agreements with over 70 countries and territories, including the UK–EU Trade and Cooperation Agreement (TCA), CPTPP membership, and bilateral agreements with Japan, Canada, Australia, New Zealand and many others. Yet for many UK businesses, the preferential tariff rates available under these agreements go unclaimed — because understanding and proving rules of origin (RoO) is genuinely complex. This guide provides a practical explainer on how rules of origin work, what you need to prove, and common pitfalls to avoid. What Are Rules of Origin? Rules of origin determine the economic nationality of goods — whether they 'originate' in a country for the purposes of a trade agreement. When goods originate in a country that has a free trade agreement with the destination country, they may benefit from a preferential (reduced or zero) tariff rate. Without meeting the relevant rule of origin, goods are subject to the standard (MFN) tariff rate regardless of where they were shipped from. The Two Main Origin Tests 1. Wholly Obtained: Goods are wholly obtained in a country if they are entirely produced there with no foreign inputs — for example, agricultural products grown in the UK, or minerals extracted in the UK. This test is simple but only applies to a narrow range of goods. 2. Substantial Transformation: For most manufactured goods, origin is determined by whether sufficient processing or transformation has taken place in the country. Substantial transformation is assessed in three ways: - Tariff Heading Change (CTH): The manufactured product has a different HS tariff heading (at 4-digit level) from all its non-originating inputs. This is the most common test. - Value Added Threshold: A minimum percentage of the product's value must be added in the originating country. UK FTAs often use 40–60% ex-works value thresholds. - Specific Process Requirements: Certain operations must be performed in the originating country (e.g., specific weaving, spinning or chemical reactions). Each FTA defines its own product-specific rules, listed in the agreement's annexes. The applicable rule for a specific product is determined by its HS commodity code. Cumulation Cumulation allows inputs from certain partner countries to be treated as if they originate in the exporting country. The UK–EU TCA, for example, includes bilateral cumulation — meaning UK manufacturers can use EU components and still claim UK origin for exports to the EU (subject to the specific rule being met). Diagonal cumulation (between multiple FTA partners) and full cumulation exist in more complex agreements. Understanding which cumulation provisions apply under a specific FTA can dramatically change a product's ability to qualify. Proving Origin: Statements and REX To claim preferential tariff treatment, the exporter must provide origin proof. Under UK FTAs this is typically either: - A Statement on Origin — a declaration made on a commercial document (invoice, delivery note, etc.) stating that the goods originate in the UK/EU/partner country. - REX (Registered Exporter System) — for higher value shipments (typically above €6,000), the exporter must be registered in the REX system to self-certify origin. Some older agreements still use EUR.1 movement certificates, though these are being phased out. Supplier Declarations Where manufacturers source components from other UK or EU suppliers, they need supplier declarations confirming the origin status of those inputs. Supplier declarations are a critical but often overlooked part of the origin documentation chain — and their absence is one of the most common reasons origin claims fail under HMRC audit. Common Mistakes - Assuming country of dispatch equals country of origin - Failing to check product-specific rules under the specific FTA being used - Not obtaining supplier declarations from the supply chain - Claiming preferences without documenting the basis of the claim - Applying the wrong cumulation rules Consequences of Incorrect Claims If HMRC or the destination country's customs authority determines that an origin claim was incorrect, the importer can be liable for the full underpaid duty — plus interest and potential penalties. For high-value or high-volume trade, incorrect origin claims carry significant financial risk. Conclusion Rules of origin are among the most technically demanding aspects of international trade compliance. Businesses exporting under UK FTAs should invest in proper training, seek specialist advice when entering new markets, and maintain robust documentation to support every preferential claim they make.