HP-2020-000016 - [2025] EWHC 1451 (Ch)

The economic evidence covered two areas: first, the question of market definition and dominance, and secondly the issue of quantification of damages. The valuation evidence solely addressed the quantification of damages. The evidence on these issues evolved considerably during the course of the proceedings.

Initial expert reports and reply reports were produced in 2022 by Liam Colley for Cabo and David Parker for MGA, covering both market definition/dominance and quantification of damages. There was then a dispute as to whether Cabo could advance, in addition to a claim for lost profits in relation to Worldeez, a further (then unpleaded) claim for the lost opportunity to develop a valuable business. At a hearing before Joanna Smith J on 24 March 2022, with an ex tempore judgment given at the hearing [2022] EWHC 702 (Pat), Cabo was given permission to amend its case to include a claim for loss of the value of the business that it would have been able to build. MGA was given permission to call an additional expert witness (Mr Davies) to address the valuation claim. Mr Colley’s second report had by then already addressed the valuation issue, and Cabo was therefore not permitted to call an additional valuation expert. Mr Colley and Mr Parker then filed a joint expert report on the issues of market definition, dominance and quantum of damages other than the valuation claim. Mr Colley and Mr Davies filed a joint report on the valuation issues.

After MGA’s additional disclosure in 2023, all three experts provided (in the course of 2024) updated individual reports and thereafter further joint reports, again with separate joint reports from Mr Colley/Mr Parker and Mr Colley/Mr Davies, respectively. During the course of preparing their revised and updated reports, all three experts collaborated on the production and population of the DTM (which is described further below). That led Mr Parker to revise his assumptions, as set out in a further report. By the end of August 2024 there were a total of 19 economic and valuation reports that had been filed: six from Mr Colley, seven from Mr Parker, two from Mr Davies and four joint expert statements.

As noted above, matters did not stop there. During September 2024 (i.e. prior to the start of the trial), and then during the course of the trial in October, up to the point at which the economic and valuation experts were cross-examined, there was a flurry of further reports and letters filled by all three experts, including documents filed by all three experts on 27 October 2024, only two days before Mr Colley was cross-examined. That gave a total of 33 economic and valuation expert reports and letters by the close of evidence in the trial.

Thereafter, since the experts had given their evidence, no further reports or letters were filed. Instead, the parties continued to update the evidence by way of legal submissions and additional calculations and models (including updates to the DTM and other excel spreadsheets) filed alongside their written closing submissions and continuing during the course of the oral closing submissions. As set out above, the parties’ final submissions on various of the quantum issues were not filed until 17 February 2025, almost a month after the end of the trial. Those submissions made further detailed comments on the economic evidence.

It is an understatement to describe this process as unsatisfactory. In the first place, the volume of expert evidence filed by the economic and valuation experts, and the multiple amendments, revisions and updates to that evidence during the course of the trial, was such that it was impossible properly to digest the new material as it came in. That made following the evolution of the evidence very challenging for both the court and the parties. It was also difficult, in these circumstances, to distinguish material issues from ancillary points of detail.

Secondly, significant shifts in position by an expert during the course of a trial may well lead the court to scrutinise the objectivity and independence of that expert’s initial opinion. That does not of course mean that an expert should stubbornly maintain their initial position simply for the sake of consistency. As the Court of Appeal has emphasised, the court will expect and encourage experts to adjust their opinions during the course of the proceedings, including during the course of the trial, in the light of emerging evidence (see for example the comments of the Court of Appeal in Royal Mail Group v DAF Trucks [2024] EWCA Civ 181, §177). Many an expert will, quite properly, concede ground when their evidence is exposed to the spotlight of cross-examination and the hard stare of the judge. Where, however, an expert completely abandons a particular part of their evidence, not as a result of any new evidence available at the trial, but rather because it is plain that the original position was untenable from the outset, that may suggest that the expert’s initial position was unduly influenced by a desire to advance their client’s case, rather than representing evidence which was the independent product of the expert, uninfluenced by the pressures of litigation, as required by CPR PD 35 §2.1.

Thirdly, and related to the second point, expert evidence at a trial is not and cannot be seen as a negotiation process, where the experts start from extremely polarised and partisan positions, only to edge incrementally towards the centre ground as the trial progresses. That would make the trial unworkable, for the parties as well as the court. The proper course is for each opposing expert to start from a position that is objective and defensible. Any differences in opinion between the experts should be discussed fully at the stage of a joint meeting of experts (if there is one). The experts should revise their opinions as appropriate following that meeting, with the joint statement reflecting their revised opinions. Any residual differences can then properly be tested through the experts’ oral evidence at the trial.

That process requires a willingness by the experts to engage with the evidence of the other side in a manner that reflects objective consideration as to the strengths and (importantly) weaknesses of their position. Where an expert fails to do so, and maintains instead an entrenched and polarised position right up to trial, that may again indicate a lack of objectivity in their approach, thereby undermining the credibility and reliability of their evidence.

In the present case, prior to the trial, the positions of Mr Colley and Mr Parker were about as far apart as could be imagined on both the questions of market definition/dominance and the quantum assessment. The result of the evolution of their positions, during the course of the trial, was that significant parts of the evidence on both sides were essentially abandoned by the end of the trial. More than that, however, on the quantum analysis both parties not only updated their figures during the trial (for example on the costs stack), but materially changed or developed their positions on significant points, with the result that on several points the position finally advanced in closing submissions was one that had not been set out in Mr Colley and Mr Parker’s expert reports, and therefore had not been tested in cross-examination.

The court is obviously required to do the best it can with the material before it, and counsel on both sides went to considerable lengths to provide submissions that were as comprehensive and helpful as possible, including (as noted above) providing further written submissions after the hearing on points which had not been fully addressed in the closing submissions. But in a case where the parties and their experts have had over four years to prepare for the trial, with multiple rounds of expert evidence over the course of a three-year period, it is very unsatisfactory for the court to be asked to consider and make findings on material which could and should have been addressed by the experts, but which did not emerge until after the hearing of the expert evidence in the trial. I consider that considerably more progress could and should have been made in the succession of expert reports and joint reports prior to the start of the trial, so that the parties’ final positions could be fully considered by the experts and properly tested in their oral evidence, rather than cobbled together in haste in the very last days of (and indeed after) a lengthy trial.

Finally, even by the end of the trialthe distance between the experts’ positions, and the evolution of the arguments, was such that there were inevitably some lacunae in the evidence. There are several different approaches which the court can adopt in that situation, depending on the nature of and reasons for the evidential gap. One approach might be to rely on the burden of proof, and to say that if there is no evidence on a particular point then the party which has the burden of establishing that point should be taken not to have proven its case. In certain types of cases, as discussed further below, evidential presumptions arising from the conduct of one or other party might also come into play. In many cases, the court will simply do the best it can on the evidence, albeit incomplete. Where appropriate the court can, however, ask for further information to be provided, particularly where that simply requires the experts to carry out further calculations on the basis of the existing underlying data.

All of those options were canvassed by the parties in the course of the trial, in relation to different issues. In most cases I have felt able to reach a conclusion on the evidence before the court, without needing to rely on the burden of proof or any evidential presumptions. On two issues, however, I asked for further calculations to be provided by the parties following the trial: (i) the market share figures implied by an extended version of Mr Colley’s market definition (§271 below); and (ii) a further version of one of Mr Parker’s quantum calculations, using a combination of Mr Parker’s price assumptions and Cabo’s cost stack (§661 below).