Sources and what we have not verified

Pages we read (21 October 2026)

• European Commission, Economic Operators Registration and Identification number (EORI): definition, who needs one, structure, where to apply, validation links.
• European Commission, EORI National implementation, 28 June 2022: formats published for some countries. Older document; national rules may have changed.
• HMRC design pattern, EORI numbers: accepted formats for GB and XI numbers and EU prefixes.
• GOV.UK, Check an EORI number: what the UK service checks and where non-GB numbers are sent.
• GOV.UK, Finding and checking an EORI: which checker covers GB, XI and EU numbers, how to find your own GB number.
• European Commission EORI validation service: official check of EU and XI numbers.
• European Commission, EORI guidance document: who registers where, database fields, duplicates, carnets, invalidation. The text we read is dated 30 August 2023.
• GOV.UK, place of registration, who should register and EORI for Northern Ireland: GB, XI and EU rules. HMRC pages updated 10 September 2025; the Northern Ireland page 7 August 2025. GOV.UK guide on using an EU EORI number for Northern Ireland: published 6 July 2026 (page data lists a change on 30 September 2026), read 7 November 2026.

Second reading, 30 October 2026

The Commission's EORI page and its 2022 national table; HMRC's introduction, "who should register" and "finding and checking" pages (updated 10 September 2025); GOV.UK's check service, apply, Northern Ireland and "which EORI" pages; the HMRC design pattern; the Commission's customs reform page; GOV.UK's low-value imports and safety and security pages; German customs' EORI questions and answers. Changes made after that reading appear in the dated edit list.

Questions still unsettled

1. Country formats beyond those listed. The Commission document we used does not state a structure for most EU countries. The checker applies only the general rule for them.
2. Greece's prefix. The checker accepts both GR and EL as country codes because we have not confirmed which one the official service uses. This is a point to verify.
3. Date of the national table. It is from June 2022 and may be outdated.
4. UK application steps. Covered on applying for a GB or XI EORI, from GOV.UK.
5. Batch size. Neither GOV.UK's checker page nor the Commission's validation page says how many numbers can be checked at once. The list mode here therefore gives you the GB numbers and the XI/EU numbers as two separate lists to copy, one for each service.
6. Country formats in the list mode. The list mode runs exactly the same rules as the single checker, including the country shapes from the Commission's 2022 table.
7. Guidance version (settled): the file the Commission lists under 29 May 2024 is the same 30 August 2023 text we read (checked 26 October 2026).
8. GB and XI length: HMRC's guidance says a GB number has 12 digits after the prefix, with XI using the same digits, and HMRC's design pattern says GB and XI numbers are 14 characters long. The same pattern's hint text also mentions 15 digits, so the checker marks a 15-digit number as possible but unusual and asks you to confirm it, rather than calling it right or wrong (re-read 30 October 2026).
9. EU numbers in the UK service. Two GOV.UK pages disagree: the place-of-registration page (10 September 2025) says EU numbers are not accepted for Northern Ireland declarations, while the EU EORI guide for Northern Ireland (published 6 July 2026; page data lists a change on 30 September 2026) lists where they work. We follow the newer guide; check both live pages.

A customs authority page that settles one of them would help; send the link through the contact details.