Court of Appeal Upholds 'Broad Axe' Principle in Royal Mail Group v DAF Trucks Competition Law Case

Citation: [2024] EWCA Civ 181
Judgment on


The case of Royal Mail Group Limited v DAF Trucks Limited & Ors ([2024] EWCA Civ 181) provides a comprehensive examination of several legal principles relating to competition law damage claims, burden and standard of proof, the assessment of damages, and the ‘broad axe’ principle. This case is pivotal for legal professionals practicing in the UK as it underscores the Court of Appeal’s approach to expert evidence and the application of competition law in follow-on damages cases. The judgment touches upon the challenges of econometric modelling and the expectations of an expert’s duty to the court.

Key Facts

The case arises from a judgment by the Competition Appeal Tribunal (CAT) concerning the quantum of follow-on damages awarded to Royal Mail and companies in the BT Group against DAF Trucks for colluding on pricing arrangements, as determined by the European Commission in 2016. The CAT awarded damages based on a finding of a 5% overcharge, which DAF Trucks appealed.

DAF’s appeal centred on four key grounds: the CAT’s alleged failure to apply the burden of proof to the claimants concerning the quantum of loss, the assertion that the CAT erred in its causation analysis specifically regarding the Supply Pass-On (SPO), the inclusion of truck bodies in the overcharge, and the approach to assessing the rate for financing losses.

Burden and Standard of Proof

The CAT held that once harm is established on a balance of probabilities, the claimant has the right to damages, and the quantification of damages must proceed using the ‘broad axe’ principle if precision is unattainable. The Court of Appeal agreed, finding no error in the CAT’s approach.

‘Broad Axe’ Principle

The ‘broad axe’ principle allows the court to estimate damages when the precise calculation is impossible, avoiding excessive demand for precision. The CAT took the position between the experts’ divergent analyses to determine a 5% overcharge. The Court of Appeal found this approach justified, given the evidential challenges and the expert’s failure to provide insights into how the cartel operated.

Expert Evidence

The Court scrutinized the over-reliance on expert evidence, the requirement for experts to demonstrate independence, and the necessity for experts to adjust their opinions based on emerging evidence. The judgment criticized DAF’s expert for a lack of transparency regarding his relationship with DAF and for expressing a theory of harm ungrounded in the practical realities of the cartel’s operation.

Supply Pass-On (SPO)

The SPO defense involves establishing that the claimant mitigated their losses by passing on the overcharge to their customers. The CAT’s majority rejected DAF’s SPO defense, citing a lack of direct and proximate causal link. The Court of Appeal concurred, emphasizing that both legal and factual causation must be satisfied.


The Court of Appeal upheld the CAT’s judgment in its entirety, dismissing DAF’s appeal on all grounds. It solidified the applicability of the ‘broad axe’ principle in quantifying damages in complex economic claims and reinforced the stringent standards expected of expert evidence in competition law litigation.


The Royal Mail Group Limited v DAF Trucks Limited & Ors case affirms the CAT’s judgment on the methodology for determining overcharge damages and clarifies the obligations of experts in providing evidence. For legal professionals, the judgment highlights the critical nature of expert evidence in competition damages claims, while consolidating the importance of adopting a realistic and fact-based approach rather than relying solely on economic theory. The case strengthens the working of the competition law regime and cements the Court’s unwillingness to permit imprecise quantifications to deny claimants rightful compensation.

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