I have transposed and updated an article on "authors" in English copyright law that I first wrote in 2002. In itself, it is pretty straightforward stuff but it links to three cases on the degree of skill and labour necessary to merit copyright protection that are not often discussed.
The first of these is Pierce v. Promco S.A., and others  EWHC Patents 275 (18 Dec 1998) a case on joint authorship that explores what Mr Justice Laddie called the "the right kind of skill and labour" in Fylde Microsystems Limited v. Key Radio Systems Limited  EWHC Patents 340 (11 Feb, 1998). Pierce is an interesting (and I think quite important) case and I surmise that the only reason why it is not discussed more is that neither side was legally represented. Inciodentally, Fylde always reminds me of a standing joke of Andrew Blackett-Ord, the last of the old style Vice-Chancellors of the County Palatine of Lancaster. The Fylde (the area around Blackpool) contains the famous fishing port of Fleetwood but it is also Manchester's Essex in more senses than one. Hence the judge's funny, "if it comes from the Fylde, gentlemen, it must be fishy."
Two Canadian cases which look at the question of the "right kind of skill and labour" from another angle are Glen Gould Estate v. Stoddart Publishing Co. Ltd., 1998 CanLII 5513 (ON C.A.) and Hager v. ECW Press Ltd. (T.D.),  2 F.C. 287, 1998 CanLII 9115 (F.C). These are essentially on Walter v. Lane,  A.C. 539 points. That is to say whether copyright belongs to the person making the speech or the person reporting it.