The judgment is here: https://www.judiciary.uk/wp-content/uploads/2024/03/Lidl-v-Tesco-CoA-Ju…

The discussion of copyright starts at paragraph 38 and permeates the remainder of the long judgment.

Paragraph 39 says "In order for copyright to subsist in an artistic work it must be “original” " and it is from that simple starting point that the case starts to have far wider application than the original dispute.

At paragraph 40, it says "The [European] Court of Justice has elaborated upon the requirement that the work be its author’s own intellectual creation in a number of subsequent judgments."

Paragraph 41 states "As can be seen from cases such as Football Dataco and Funke Medien, the European test is not the same as the test of “skill and labour” applied by the English courts prior to 2009, and the European test is more demanding. On the other hand, Painer establishes that even a simple portrait photograph may satisfy the European test in an appropriate case.

Paragraph 42 says "Four points should be noted about the application of this test. First, the test is an objective one. Secondly, the test is not one of artistic merit: section 4(1)(a) of the 1988 Act expressly provides that graphic works qualify as artistic works “irrespective of artistic quality”, and nothing in the case law of the CJEU suggests otherwise. Thirdly, the burden of proof lies on the claimant, here Lidl. Fourthly, particularly in a case concerned with graphic works, a key item of evidence is the works themselves."

Paragraph 43: "Copyright in an artistic work is only infringed if a “substantial part” of the work has been copied."

Taking all of these together, the rights of content creators are prima facie established and sustainable if they can identify "a substantial part" of their work has been copied and replicated.

So the question in "generative AI" cases is going to go beyond "is there copying" but " is that copying substantial"?

The "substantial" test relates to the proportion of the original work not to the proportion that the material bears to the work which is alleged to infringe the copyright.

But, as we know from music sampling cases, only a few notes can be regarded as substantial although, as we can all tell from watching tv and films, many pieces are closely replicated but not directly copied, so avoiding copyright claims.

The Lidl - Tesco case is important because the detailed analysis set out in the judgment is a template that can be followed in relation to "generative AI" - but does it help creators?

Probably not much because Lord Justice Birss in a judgment that was partially dissenting said (para 222) "I find myself in the position of Lord Bridge of Harwich in the Jif Lemon case at 495:
“If I could find a way of avoiding this result, I would. But the difficulty is that the trial judge’s findings of fact, however surprising they may seem, are not open to challenge. Given those findings, I am constrained … to accept that the judge's conclusion cannot be faulted in law. With undisguised reluctance I agree … that the appeal should be dismissed.”

And with that, Tesco's appeal was dismissed. There are no obvious grounds for appeal to the Supreme Court but these are two heavyweight sluggers going at it over a petty point (Tesco could have said "sorry: we'll change the logo" instead of running up, probably, millions in legal fees and have suffered no adverse commercial consequences.

Birss, LJ's concern did not relate to the copyright aspects of the case but to the trade mark aspects. It follows, then, that the judgment of Arnold, LJ stands in respect of those.