The UK–EU Trade and Cooperation Agreement (TCA), which came into force on 1 January 2021, represented the largest trade policy change for UK businesses in a generation. Three years into its implementation, a clearer picture has emerged of what the agreement delivers in practice — and where it falls short of seamless trade. What the TCA Provides At its core, the TCA provides zero tariffs and zero quotas on trade in goods between the UK and EU — but only for goods that meet the applicable rules of origin. This is a crucial distinction from the frictionless single market access that UK businesses previously enjoyed as EU members. The TCA also covers services (to a degree), data adequacy, fisheries, aviation, road transport and a wide range of technical cooperation arrangements. However, the UK's exit from the Single Market and Customs Union means that full non-tariff barriers — in the form of customs declarations, sanitary and phytosanitary checks and regulatory divergence — now apply to UK–EU trade in a way they did not before. The Reality of Rules of Origin The rules of origin requirements under the TCA have proved to be one of the most significant practical challenges for UK manufacturers and exporters. To benefit from zero tariffs, goods must originate in either the UK or EU under the product-specific rules set out in the TCA's annexes. For manufacturers sourcing materials globally, this has required significant supply chain review. The automotive sector in particular has faced challenges around the rules of origin for electric vehicles, where battery content requirements tighten over time (initially 70% UK/EU content, rising to 55% from 2027 under revised rules). Customs Friction The introduction of customs controls at the UK–EU border has added cost and complexity to supply chains in both directions. UK businesses exporting to the EU now face EU customs entry requirements, and EU exporters to the UK face UK customs declarations. The full suite of UK border controls was progressively implemented through 2022 and 2023, including: - Full customs declarations on EU imports - Safety and security declarations (the UK Safety and Security Declaration regime) - Health certificates for products of animal origin - Phytosanitary certificates for regulated plant products The Government's Border Target Operating Model, introduced in 2023/2024, has sought to streamline these requirements, but additional administrative burden remains compared to the pre-Brexit position. Sector-Specific Impacts Food and Drink: The sector has been one of the most significantly affected by TCA implementation. New SPS requirements, export health certificates and the administrative burden of border documentation have reduced UK food exports to the EU and raised costs for both importers and exporters. Manufacturing: Rules of origin compliance costs have fallen most heavily on manufacturers. The need to track and document origin in a way never previously required — through supply chains that were designed for single market operation — has added administrative overhead. Professional Services: The TCA provides limited mutual recognition for professional qualifications, and UK professionals can no longer rely on automatic recognition of their credentials across EU member states. This has complicated service delivery for accountants, lawyers, engineers and others seeking to work in EU markets. Financial Services: The loss of passporting rights for UK financial services firms means that UK banks, asset managers and insurers can no longer offer services freely across the EU. Equivalence determinations have been partial and subject to political uncertainty. Opportunities Under the TCA Amid the challenges, the TCA has also created positive opportunities for UK businesses: - The UK's ability to strike its own FTAs independently (CPTPP, Japan, Australia, New Zealand, etc.) opens new market access pathways - Regulatory divergence creates the potential for UK-specific regulatory environments that may benefit certain sectors - The UK's independent trade policy creates opportunities to source from new trading partners on more favourable terms Conclusion The TCA is a substantial agreement that has prevented significant tariff escalation on UK–EU trade. However, the framing of zero tariffs as the primary measure of success has sometimes obscured the very real non-tariff costs that customs friction, rules of origin compliance and regulatory divergence have introduced. UK businesses that have invested in adapting to the new framework are operating more effectively; those that have not are carrying ongoing costs they may not have fully quantified.