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.

Points we could not settle

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 It is from June 2022 and may be outdated.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. Not summarised here; see GOV.UK.
5. Batch size and invalid results. The GOV.UK page we read does not say how many numbers can be checked at once or what to do when a check says invalid.
6. Country formats. The list mode applies the same general rule as the single checker.
7. Guidance version. The Commission lists a version dated 29 May 2024; the text we read is dated 30 August 2023. Newer wording has not been read.
8. GB and XI length. HMRC says 14 characters and also 12 or 15 digits after the prefix. We accept both and have not found an official statement that settles it.
9. EU numbers in the UK service. HMRC says they are not accepted for Northern Ireland declarations until further notice. Check the live page.

A customs authority page that answers one of these would help; send the link through Contact.