CA-2025-000517 - [2025] EWCA Civ 1061

B.The evaluation of evidence and inferences of fact

The Court of Appeal has jurisdiction in appeals of this sort only on points of law: section 49(1) CA 1998. Where an issue focuses upon an evaluation of evidence it is, at least in principle, capable of amounting to an error of law in some circumstances: see e.g. Airwave Solutions Limited v CMA [2025] EWCA Civ 54 at paragraphs [88] and Cinven (ibid) at paragraphs [161], [242] – [243]. Classic illustrations are where the CAT acted irrationally in its findings in the sense that no CAT could, acting reasonably, arrive at the conclusion that it did, or failed to address relevant considerations, or took into account irrelevant considerations. However, this Court has to ensure that it does not, without good and proper reason, interfere in the exercise of the legitimate discretion of the CAT to find facts and draw inferences from those facts. Both the nature of the evidence and the institutional composition of the CAT are factors affecting the breadth of the margin of discretion that must be accorded to the CAT and this impacts upon the sorts of alleged errors that the Court will recognise as amounting to viable grounds of appeal:

First, many issues to be decided about the computation of Cost-Plus and the justification for the differential with selling prices are incapable of precise measurement or quantification. The complexity of the task is multiplied because many cases resemble large multi-piece jigsaws. The CAT has to form conclusions based upon data exhibiting varying degrees of accuracy and completeness which may also be based upon assumptions of uncertain precision and authenticity meaning that routinely it must make judgment calls about the reliability of multiple strands of divergent and inconsistent evidence. In doing this the CAT has to use its powers of informed, skilled, guesstimation, or, to use the more colourful analogy deployed in other cases, wield the broad axe.

Secondly, the CAT has an institutional ability on the Bench to meld legal, financial, business and economic experience, a range of skills not systemically replicated in an appeal Court, but which are especially important in cases such as the present given the nature of the evidence. Where a finding concerns how to identify relevant costs, or as to their attribution once identified to a line of business or, assuming it is to be attributed, as to the extent of the allocation, or as to the assessment of the value to consumers of various features of a good or service both in the index market and/or in a comparable market, or as to the relationship between value and final selling price, the appellate court is in a materially weaker position to form a fair and rounded conclusion, than is the CAT. This is why its jurisdiction is limited to points of law and why, where disputes over evidence and fact are said to amount to appealable points of law, the Court exercises considerable reticence before interfering in the CAT’s evaluative judgment.