Following the United Kingdom's departure from the European Union, Northern Ireland occupies a unique position that affects how businesses identify themselves for VAT and customs purposes. This guide explains the XI-prefix numbers used for Northern Ireland and when they apply.
Under the Protocol on Ireland/Northern Ireland (as modified by the Windsor Framework), Northern Ireland maintains a special relationship with both the EU and Great Britain regarding trade in goods. While politically part of the UK, Northern Ireland remains aligned with EU customs and VAT rules for goods moving between it and the EU.
This creates a situation where Northern Irish businesses may need multiple identifiers depending on the nature of their trade:
VAT-registered businesses in Northern Ireland that trade in goods with the EU receive an XI-prefix VAT number in addition to their GB VAT number. The XI number allows them to participate in the EU VAT system for goods transactions.
XI VAT numbers follow the same format as GB VAT numbers but with XI as the country code:
Use an XI VAT number when:
XI VAT numbers can be verified through VIES, the EU's VAT Information Exchange System, just like VAT numbers from EU member states. Enter the full XI number in the VIES validation tool to check its validity.
For customs purposes, Northern Irish businesses trading goods with the EU use XI-prefix EORI numbers. These numbers function within the EU customs system despite Northern Ireland being part of the UK.
Use an XI EORI number when:
XI EORI numbers can be verified through the EU EORI validation tool, the same system used for EU member state EORI numbers.
Understanding when to use GB versus XI numbers is crucial for compliance:
For businesses in England, Scotland, and Wales, the situation is different. GB VAT and EORI numbers are not part of the EU system and cannot be verified through VIES or the EU EORI database.
GB VAT numbers (format: GB + 9 or 12 digits) must be verified through HMRC's VAT validation service. They cannot be used for EU intra-community trade purposes.
GB EORI numbers (format: GB + 12 or 15 digits) are required for customs declarations in Great Britain and for trade with non-EU countries. They must be verified through HMRC's EORI checker.
If you are an EU business trading with UK counterparts:
Trading with Northern Ireland: You can verify their XI VAT numbers through VIES and conduct trade under familiar intra-community rules for goods. The XI number enables zero-rating and reverse charge mechanisms.
Trading with Great Britain: You cannot use VIES to verify GB VAT numbers. Trade with GB is treated as export/import with customs declarations required. You may need to work with customs agents and understand UK import VAT rules.
Northern Irish businesses typically obtain XI numbers through HMRC when they register for VAT or apply for an EORI. Businesses that already had UK VAT registration before Brexit were generally assigned XI numbers automatically if they declared trade in goods with the EU.
If you are a Northern Irish business needing XI numbers, contact HMRC to ensure your registrations are properly configured for EU goods trade.
The Windsor Framework, agreed in 2023, modified certain aspects of the original Northern Ireland Protocol. For verification purposes, the core principles remain unchanged: XI numbers continue to provide Northern Irish businesses access to EU VAT and customs systems for goods trade. However, the framework introduced simplified arrangements for certain goods movements and reduced documentary requirements for trusted traders.
Businesses should monitor official guidance from both HMRC and the European Commission for ongoing updates to these arrangements. The framework includes provisions for future evolution of the trading relationship that may affect identifier requirements.
Generally, no. XI numbers are specifically for businesses established in Northern Ireland. A Great Britain business without a Northern Ireland establishment cannot obtain XI numbers. However, GB businesses may establish a presence in Northern Ireland specifically to access XI registration, though this requires genuine business substance.
No. EU businesses use their standard EU VAT and EORI numbers when trading with Northern Ireland. The XI number requirement applies to the Northern Irish party in the transaction, not to EU counterparts.
If an XI VAT number fails verification in VIES, first confirm the number is entered correctly, including the XI prefix. If the number is correct but still fails, the business may not be properly registered for EU goods trade. Request confirmation from the Northern Irish business and suggest they contact HMRC to verify their XI registration status.
| Number Type | Verification System |
|---|---|
| XI VAT (Northern Ireland) | VIES |
| XI EORI (Northern Ireland) | EU EORI Validation |
| GB VAT (Great Britain) | HMRC VAT Check |
| GB EORI (Great Britain) | HMRC EORI Checker |
For general verification guidance, see our VAT Verification and EORI Verification guides.
