Proof of Origin after Brexit – EUR.1 vs REX vs Statement on Origin [when to use which]

Since Brexit, trade between the European Union and the United Kingdom has been governed by the Trade and Cooperation Agreement (TCA) — and it is this agreement that determines whether your goods will attract customs duty at the border or not. The good news: most goods qualifying as "originating in the EU" or "originating in the UK" can benefit from a preferential duty rate of 0%. The bad news: the TCA provision alone is not enough — you must prove that origin with the correct document. This is where confusion sets in, because three terms are often mixed up: EUR.1, REX and statement on origin. In UK–EU trade the proof is a statement on origin (or the importer's knowledge), REX is the EU exporter's number, and EUR.1 is not used. This article explains exactly when each applies, who may issue it, how to register in the REX system, and what happens when a customs officer finds an error in your proof of origin. You will also find information on cumulation rules, which are often overlooked yet can determine whether your product qualifies for 0% duty at all.

Why proof of origin is critical after Brexit

Before Brexit, goods moved freely between the UK and the EU without duties and without any need to prove where they came from. From 1 January 2021 everything changed. The TCA introduces a 0% duty rate — but only for goods that meet the Rules of Origin. Without a valid proof of origin, the customs officer will assess full MFN (Most Favoured Nation) duty, which depending on the product can range from a few to several dozen per cent.

The rules on proof of origin are published on gov.uk.

The key question is: does your product actually qualify as "originating in the EU" or "originating in the UK"? The answer is not always obvious. The TCA contains detailed rules — for example, a requirement for "sufficient processing" or the satisfaction of added-value criteria. Only once a product qualifies for the preference do you choose the appropriate type of proof.

Comparison of proof of origin options in UK–EU trade

Under the TCA, the importer claims preference on the basis of one of two proofs: a statement on origin made out by the exporter, or the importer's knowledge. The EUR.1 certificate is not used in UK–EU trade. REX is not a separate document but the EU exporter's reference number entered in the statement on origin.

Feature	Statement on origin	Importer's knowledge
Made out by	Exporter (on the invoice or another commercial document)	Importer, based on information on the product's origin
Exporter reference number	EU exporter: REX number (needed for consignments with a total value above EUR 6,000); UK exporter: EORI number	Not applicable
Validity	Imports to the UK: 2 years from the date made out; exports to the EU: 12 months	—
Condition	The goods must meet the TCA product-specific rules of origin

EUR.1 – is it used in UK–EU trade?

No. The EUR.1 movement certificate is not a proof of origin under the UK–EU TCA. GOV.UK guidance lists only a statement on origin made out by the exporter and the importer's knowledge. If a counterparty asks for an EUR.1 for a UK–EU shipment, the correct document is a statement on origin.

Tip: if you regularly export consignments worth more than EUR 6,000 from the EU to the UK, you need a REX number to make out a statement on origin.

REX – Registered Exporter System: how it works and how to register

REX is the registered exporter system that allows you to declare the origin of goods yourself, without involving the customs authority. It is designed for companies that export regularly to the UK and want to save time and money.

How REX works: - The exporter registers once in the REX database - Once a REX number is obtained, the exporter can self-certify origin declarations on commercial invoices or other commercial documents - There is no consignment value limit - A REX exporter may also issue a statement on origin for consignments above EUR 6,000

How to register as a REX exporter in Poland: 1. Submit an application electronically via the PUESC portal (portal.puesc.gov.pl) 2. Attach company registration documents and a declaration confirming knowledge of the Rules of Origin 3. Processing time: usually 5–10 working days 4. You receive a REX number in the format: PL/REX/XXXX/XXXX 5. The number appears in the European Commission's public REX database

Obligations of a REX exporter: - The exporter is personally responsible for the accuracy of declarations - Supporting documentation confirming that the Rules of Origin are met must be retained for at least 4 years - Incorrect declarations may result in revocation of REX status and liability for unpaid duty

Statement on origin – for small consignments and REX exporters

A statement on origin is a declaration placed on a commercial invoice or other commercial document stating that the goods originate in the EU (or the UK). It is the simplest form of proof of origin.

When a statement on origin may be issued WITHOUT REX registration: - Only when the consignment value does not exceed EUR 6,000 - The declaration may be entered directly on the commercial invoice

When a REX exporter may issue a statement on origin: - For consignments of any value - On the invoice, waybill or another commercial document

Wording of a statement on origin in accordance with the TCA:

The exporter of the products covered by this document (Exporter Reference No. [REX number of the EU exporter or EORI number of the UK exporter]) declares that, except where otherwise clearly indicated, these products are of [EU or UK] preferential origin.

[Place and date]
[Exporter's signature]

Note: the absence of a REX number on a consignment worth more than EUR 6,000 will invalidate the declaration and result in full duty being assessed by UK customs.

What UK customs checks when examining proof of origin

HMRC (His Majesty's Revenue and Customs) checks the following when inspecting proof of origin:

1. Formal document requirements — whether the REX number (EU exporter) or EORI number (UK exporter) is valid and whether the statement on origin contains all required elements
2. Consistency with the commercial invoice — the value, goods description, and quantity must agree
3. Rules of Origin — whether the HS code of the goods can qualify for TCA preferences at all and whether the declared origin is plausible
4. Expiry dates — for imports to the UK a statement on origin is valid for 2 years from the date it was made out

What happens if the proof of origin is incorrect: - The importer pays full MFN duty (no preference) - HMRC issues a demand for payment with interest on the duty that was not paid at the time - If fraud is suspected — a formal investigation is opened - The EU exporter may be notified by EU customs authorities of the need for post-clearance verification

Cumulation rules – when materials from another country "count" towards origin

Cumulation is a mechanism that allows materials or processing carried out in a partner country to be treated as one's own. In the context of the UK–EU TCA there is bilateral cumulation: materials "originating in the UK" used in EU production may be treated as EU materials, and vice versa.

Practical example: a furniture manufacturer in Poland uses metal components from the UK. When calculating whether an armchair meets the Rules of Origin for export to the UK, the UK components count towards the "EU/domestic" value. This can determine whether the product qualifies for the preference at all.

Key limitation: cumulation only applies where the final processing exceeds "minimal operations". Simple assembly of basic components is often insufficient.