Windsor Framework
The 2023 UK-EU agreement that replaced the Northern Ireland Protocol, setting the rules under which Northern Ireland businesses use XI-prefix VAT numbers for goods trade with the EU.
What it is
The Windsor Framework is the agreement between the UK and the EU signed in 2023 that revised the original Northern Ireland Protocol (in force since January 2021). The Protocol had been put in place to avoid a hard customs border between Northern Ireland and the Republic of Ireland after Brexit, while the UK as a whole left the EU single market and customs union. The Windsor Framework adjusted the governance and practical arrangements without changing the core VAT principle: Northern Ireland remains within the EU VAT area for goods.
Where you meet it
The Windsor Framework is the legal basis for why Northern Irish businesses continue to use XI-prefix VAT numbers registered in VIES for goods trade with EU customers. For VAT validation purposes, the Framework did not change what was already in place under the Protocol. XI numbers existed before the Framework, and they continue to exist after it.
What changed and what did not
The Windsor Framework introduced the "Stormont Brake" mechanism, which allows the Northern Ireland Assembly to flag concerns about new EU rules automatically applying to Northern Ireland. This is a governance mechanism and has no direct effect on how VAT numbers work.
For VAT: Northern Ireland businesses selling goods to EU buyers use XI numbers through VIES. Northern Ireland businesses selling services, or making purely domestic UK sales, use GB numbers through HMRC. This distinction predates the Framework and was not altered by it.
Common confusions
- "Windsor Framework" and "Northern Ireland Protocol" are sometimes used interchangeably in older documentation. They refer to different instruments, but for VAT purposes the practical rules are the same.
- The Framework did not move Northern Ireland back into the UK customs union for goods. XI numbers remain valid for EU goods trade.