You need an EORI number to move goods between Great Britain (England, Scotland and Wales) or the Isle of Man, and other countries. You may also need a separate EORI number if you move goods to or from Northern Ireland.
If you do not have an EORI, you may have increased costs and delays. For example, if HM Revenue and Customs (HMRC) cannot clear your goods you may have to pay storage fees.
If you already have an EORI number and it does not start with GB you will need to apply for a new one.

 

Source: Gov.UK website