Research conducted within Translation Studies has traditionally focused on comparing translations with their source texts. In recent years, however, much corpus-based research has set out to compare translated and non-translated text in the same language on the basis of what has come to be known within corpus-based Translation Studies as 'comparable corpora'. Comparable corpora in this context consist, on the one hand, of texts translated from a variety of source languages into a given language, say English, and, on the other, of a 'comparable' corpus of non-translated texts in the same language. The two corpora are matched as closely as possible in terms of time frame and domain/genre. This paper offers a brief comparison between translated and non-translated English in relation to the use of idioms on the basis of evidence drawn from the Translational English Corpus held at the University of Manchester and a comparable subset of the British National Corpus.