Case Nos: CA-2024-002655/002675/002676 - [2025] EWCA Civ 936

Conclusion

For the reasons given above I would dismiss the appeal.

Lord Justice Snowden:

I agree.

Lord Justice Zacaroli:

I also agree. As Arnold LJ has pointed out, a conclusion on obviousness is a highly fact-dependent evaluative decision where the judge who has been immersed in the detail of the case has a significant advantage over an appellate court. That is particularly so in a specialist area in which the judge is well-versed, and where the judge has heard the cross-examination of the technical experts. The judge’s findings that Professor Westwell’s conclusion was tainted with hindsight  and failed to identify the context for what was technically obvious are themselves fact-dependent aspects of that overall evaluative decision. I agree with Arnold LJ that the Claimants’ arguments on appeal do not reach the threshold for establishing that those findings involved an error of law or principle.