Many aspects of the guidelines of the Text Encoding Initiative (TEI) are applicable to corpora and text collections, and to the texts that these contain. As the first large corpus developed using mark-up conforming to the guidelines, the British National Corpus (BNC) is a test-bed for many TEI-developed mechanisms. This is particularly true in the case of the TEI header, which has three intended applications — to describe a corpus, to describe an individual text, and as a free-standing bibliographic record — all of them used by the BNC. This paper describes the application of the TEI header to the BNC. It is intended that this information should, through a description of experience on a practical project, serve as a guide for those wishing to use TEI headers in the documentation and management of other corpora and collections of texts.