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HMRC internal manual

Customs Special Procedures Manual

Co-storage: identification of goods

Union goods and goods under Inward Processing (IP) must be clearly identifiable from goods under the customs warehousing arrangements. The warehouse keeper must be able to identify both physically and in the records the goods under the respective customs procedures and the Union goods. If necessary, you can require the authorisation holder to mark or label such goods to ensure that goods of different status can be readily identified.

2015/2446 Article 178