Abstract This paper examines patterns of metaphor in usage. Four samples of text excerpts of on average 47,000 words each were taken from the British National Corpus and annotated for metaphor. The linguistic metaphor data were collected by five analysts on the basis of a highly explicit identification procedure that is a variant of the approach developed by the Pragglejaz Group (Metaphor and Symbol 22: 1–39, 2007). Part of this paper is a report of the protocol and the reliability of the procedure. Data analysis shows that, on average, one in every seven and a half lexical units in the corpus is related to metaphor defined as a potential cross-domain mapping in conceptual structure. It also appears that the bulk of the expression of metaphor in discourse consists of non-signalled metaphorically used words, not similes. The distribution of metaphor-related words, finally, turns out to be quite variable between the four registers examined in this study: academic texts have 18.5%, news 16.4%, fiction 11.7%, and conversation 7.7%. The systematic comparative investigation of these registers raises new questions about the relation between cognitive linguistic and other approaches to metaphor.