To prove copyright infringement, the claimant has the onus of proving two things: first the alleged infringer created his or her work by copying from the copyright owner’s work (copying in fact); second, that all or a substantial part of the original work was copied (illicit copying). The analytical steps in each inquiry have been considered in numerous cases. For example, the Supreme Court of Canada reviewed the steps a Canadian court should follow in establishing illicit copying in a “altered copying” case in Cinar Corporation v. Robinson, 2013 SCC 73 (summarized here).
Last week, a UK court reviewed the leading cases on this issue in John Kaldor Fabricmaker v Lee Ann Fashions  EWHC 3779. Judge Hacon of the Intellectual Property Enterprise Court summarized the principles to be applied in the UK as follows:
(1) The first stage is to consider whether the claimant has established a prima facie inference of direct or indirect copying by reason of the similarities between the copyright work and the defendant’s work.
(2) Similarities which constitute the expression of ideas that have no connection with the literary, dramatic, musical or artistic nature of the work are to be disregarded.
(3) Similarities not thus excluded but which are shown to be commonplace give rise to little or no inference of copying; the nearer a similarity approaches the strikingly original end of the spectrum, the greater weight it carries in supporting an inference of copying.
(4) If the claimant establishes a prima facie case of inferred copying, this may be rebutted by the defendant’s evidence of independent design. The stronger the prima facie case, the more cogent the defendant’s evidence must be to rebut the inference.
(5) If there is no finding of copying, there is no infringement. If there is a finding of fact that there has been copying, the next stage is to consider whether copying was done either in relation to the copyright work as a whole or any substantial part of it.
(6) Designers Guild sanctions two alternative approaches to the question of substantial part. They are alternatives because neither was expressly endorsed by a majority. The first is to disregard the defendant’s work and to assess whether the similarities from which an inference of copying was drawn constitute a substantial part of the copyright work. This is a qualitative, not a quantitative assessment. The second, which applies only in an instance of altered copying, is to determine whether the infringer has incorporated a substantial part of the intellectual creation of the author of the work. In many cases the difference between the two approaches to an allegation of altered copying may be limited.
(7) To the extent that it has not already been excluded under step (3), a commonplace similarity can in any event make no contribution to any substantial part of the copyright work alleged to have been copied since it is not capable of attracting copyright protection.
(8) Assessment of whether there has been copying of a substantial part of the copyright work is a necessary and distinct step in the determination of whether the defendant has infringed. However, where copying has been established, on the facts it may be that this will almost inevitably lead to the conclusion that a substantial part of the copyright work has been copied. This may be influenced by the degree to which the finding of copying depended on the similarities between the two works.