While corpus linguistics has existed since the 1960s, Forensic Linguistics is a relatively new discipline, involving both linguistic evidence in court and wider applications of linguistics to legal texts and discourses. Computer corpora of natural language may be marked up in various ways, grammatically tagged, parsed, lemmatised and analysed with concordance, collocation and other specialist soft ware. In the relatively short history of forensic linguistics, its exponents have oft en employed corpus linguistics techniques in order to throw light on questions like disputed authorship. However, the corpora employed have been general ones such as the Cobuild “Bank of English”, rather than purpose-built databases of language used in legal contexts, with the result that such research sometimes raises more questions than it answers. Conversely, corpus linguists have from time to time incorporated data from legal settings into their collections; but they have tended to use these resources as the basis for sociolinguistic or historical linguistic research rather than as a means of exploring topics in language and law. This paper makes a plea for these two fi elds, which are both already cross-disciplinary, to join forces and create a purpose-built corpus for forensic linguistics. It illustrates how corpus techniques may be successfully applied to questions of disputed authorship, citing both hypothetical and actual examples. It ends with an outline of the kinds of texts which a proposed new corpus for Forensic Linguistics should contain and the tools required to exploit it eff ectively.