"Fair dealing" is often confused by those who ought to know better with the American concept of "fair use" . I have seen references to "fair use" more than once in English licence agreements. The US concept is very different as is made clear by the Canadian case Hager v. ECW Press Ltd. (T.D.),  2 F.C. 287, 1998 CanLII 9115 (F.C.).
It seems from Mr Justice Souter's judgment in Campbell and others v Acuff Rose Music Ltd. (92-1292), 510 U.S. 569 (1994). that the American doctrine derived from the English case Carey v. Kearsley, (1803) 4 Esp168, but if that is the case it is just one example of the divergence of English and American copyright law like the American concept if divisibility of copyright and non-copyright material in the same work compared to the English and Commonwealth concept of substantiality.