On 7 May 2021, the Court of Appeal dismissed the appeal by Royal Mail plc (Royal Mail) of a judgment by the CAT of 12 November 2019. The CAT had upheld Ofcom’s August 2018 decision to fine Royal Mail £50 million for abusing its dominant position in the wholesale market for bulk mail delivery services by issuing Contract Change Notices which introduced discriminatory prices. Royal Mail appealed the CAT judgment on two closely-related grounds, arguing that the Tribunal had erred in law in finding that:(i) an “as efficient competitor” (AEC) test was irrelevant when assessing whether the action would give rise to likely anti-competitive effects; and (ii) Ofcom had given adequate consideration to the AEC analysis put forth by Royal Mail. The Court of Appeal held that “Ofcom was not required as a matter of law to treat the AEC test as either determinative or highly relevant. In those circumstances Ofcom gave adequate consideration to the AEC test, and the Tribunal did not err in law in so concluding.