Trade between Spain and the United Kingdom remains one of the most dynamic in Europe, but since 1 January 2021 it has operated under rules that are completely different from those of the single market. Five years on, many businesses still aren’t entirely clear on what exporting to the UK (Brexit 2026) actually involves: which documents are mandatory, how tariffs are calculated, and which border controls apply to each shipment.
In this guide from Sile Customs Broker we go through, step by step, everything you need to know about exporting to the UK after Brexit in 2026: the required documentation, the tariff treatment under the Trade and Cooperation Agreement (TCA), the controls of the new Border Target Operating Model (BTOM), and the mistakes that cause the most delays at British customs.
Key points
Everything you need to know about exporting to the UK (Brexit 2026), at a glance:
- ✓The UK is a third country: every export requires a customs declaration, whether or not a tariff applies.
- ✓You need, at minimum, an EORI number, commercial invoice, packing list, proof of origin and an export declaration (DUA/EAD).
- ✓With the TCA and a valid proof of origin, the tariff can be 0%; without it, the general UK tariff applies.
- ✓The Border Target Operating Model (BTOM) already requires pre-notification and physical checks in 2026 for sanitary and phytosanitary goods.
- ✓A customs agent reduces the risk of holds, penalties and logistics overspend on every shipment.
The UK, a third country: what exporting there means in 2026
Since leaving the single market and the European customs union, the UK is treated in every respect as a third country. This means that any shipment between Spain and the UK, in either direction, requires a formal customs declaration, exactly as if you were exporting to the United States or China.
The framework governing this trade relationship is the Trade and Cooperation Agreement (TCA), in force since 1 January 2021, which allows trade at a preferential 0% tariff provided the goods meet the rules of origin agreed between the EU and the UK. That said, the TCA doesn’t remove customs bureaucracy: it only avoids, under certain conditions, the payment of tariffs.
On top of this, since 2024 the UK has been progressively rolling out the Border Target Operating Model (BTOM), the new border control system that by 2026 is fully in force across all its phases, tightening documentary and sanitary requirements for certain goods.
Documents for exporting to the UK after Brexit
Before scheduling any shipment, it’s worth having the full documentation ready. These are the mandatory documents for exporting to the UK in 2026:
- Spanish EORI number (ES prefix), essential for filing any export customs declaration with the Spanish Tax Agency (AEAT).
- Commercial invoice, with an exact description of the goods, their value, delivery terms and the agreed Incoterm.
- Packing list, detailing the number of packages, weight and volume of the shipment.
- Proof of preferential origin (a statement on origin on the invoice or a certificate, depending on the value of the operation), needed to apply the 0% tariff under the TCA.
- Export declaration (DUA/EAD), filed in Spain with the Tax Agency before the goods leave EU territory.
- UK import declaration, filed by the British importer or their customs representative once the goods arrive.
- Specific licences or certificates (sanitary, phytosanitary, CITES, dual-use) where the product requires them.
The Incoterm you negotiate with your British customer determines who takes on each of these formalities and their associated costs. If you’re still not sure which arrangement suits you, take a look at our guide on Incoterms 2020: types, what they are and how to choose the right one before signing the sales contract.
Tariffs when exporting to the UK in 2026: how they work
The tariff treatment of your export mainly depends on whether you can prove the preferential origin of the goods under the TCA.
Preferential 0% tariff under the TCA
If your product meets the rules of origin of the Trade and Cooperation Agreement (for example, a minimum percentage of components or processing carried out in the EU) and you provide the corresponding proof of origin, the import into the UK can be exempt from tariffs. This is the usual route for most Spanish exports.
General tariff (UK Global Tariff) without preferential origin
If you can’t prove preferential origin, the goods are taxed under the UK Global Tariff, the general tariff the UK applies to third countries without an agreement, similar in logic to the EU’s TARIC. The rate varies according to the tariff classification of the product, which makes correctly classifying the commodity code just as decisive as in any other international trade operation.
In addition to the tariff, the British importer will need to settle import VAT under UK tax rules, a cost that falls on their side of the deal unless the agreed Incoterm (for example, DDP) shifts that responsibility to the exporter.
Border controls in 2026: the Border Target Operating Model (BTOM)
The BTOM classifies goods by their risk level (low, medium or high) and, depending on that category, requires different levels of control when entering the UK:
- Mandatory pre-notification through the IPAFFS system for products of animal, plant or food origin, before the goods reach the border.
- Documentary and identity checks on the sanitary and phytosanitary certificates accompanying the shipment.
- Physical inspections at Border Control Posts for medium- or high-risk goods.
A shipment that arrives without the corresponding pre-notification, or with incomplete sanitary documentation, risks being held at the border, with the resulting storage costs and delays.
When do you need a customs agent to export to the UK?
Most SMEs exporting to the UK for the first time underestimate the documentary complexity a third country involves, especially since the BTOM came into force. Getting the right support stops being optional in these scenarios:
- A first export operation to the UK, with no previous experience outside the EU.
- Products subject to sanitary, phytosanitary or specific licensing controls.
- The need to prove preferential origin in order to apply the TCA’s 0% tariff.
- Recurring shipments where every border delay means a repeated logistics cost.
If you want to understand exactly what this role covers and when it’s worth hiring one, read our guide on what a customs agent is and when your business needs one. At Sile Customs Broker we support Spanish businesses in their UK operations, from tariff classification through to filing the export DUA.
Common mistakes when exporting to the UK after Brexit
- Assuming Brexit is “already sorted” and operating as if the UK were still in the single market, without a customs declaration.
- Not having proof of origin to claim the TCA’s preferential tariff, ending up paying a tariff that could have been avoided.
- Skipping the IPAFFS pre-notification for shipments of animal, plant or food products subject to the BTOM.
- Misclassifying the goods, which throws off both the UK tariff and the applicable controls.
- Not coordinating the Incoterm with the British customer, creating confusion over who covers VAT and the import clearance at destination.
Frequently asked questions about exporting to the UK (Brexit 2026)
Do I need an EORI number to export to the UK?
Yes. You need a Spanish EORI number (ES prefix) to file the export declaration in the EU, and your British customer will need their own UK EORI number (GB prefix) to file the import declaration at destination.
What tariffs do I pay if I export to the UK in 2026?
It depends on the origin of the goods. If you can prove preferential origin under the TCA, the tariff can be 0%. If you can’t prove it, the UK Global Tariff applies according to the product’s tariff classification.
What is the BTOM and does it affect me if I export to the UK?
The Border Target Operating Model is the UK’s border control system, with phases already fully in force in 2026. It particularly affects sanitary, phytosanitary and food products, which require pre-notification through IPAFFS before reaching the border.
Is Brexit still relevant in 2026, or has something changed?
The overall TCA framework remains in force, but UK border controls have evolved significantly since 2021: the BTOM was rolled out in phases between 2024 and 2025, and by 2026 it requires more documentation and physical checks than in the first years after Brexit.
Can I use the same Incoterms as before Brexit?
Incoterms 2020 are still valid, but you should review who handles customs clearance and import VAT in the UK, since these obligations change substantially compared with an intra-EU operation.
Export to the UK without surprises in 2026
Five years after Brexit, exporting to the UK (Brexit 2026) still requires documentary precision and correct tariff planning. Knowing the mandatory documents, how the TCA works, and the new BTOM requirements is the difference between a smooth shipment and goods held at the border.
Is your business preparing its next export to the UK? At Sile Customs Broker we handle the documentation, tariff classification and clearance of your shipments to the British market. Get in touch with our team and operate without surprises.