Competition Appeal Tribunal Rejects Proposed Claims in Water Collective Proceedings

On 7 March 2025, the Competition Appeal Tribunal (CAT) delivered its judgment[1] in respect of applications made by Professor Carolyn Roberts, the proposed class representative (PCR) for collective proceedings orders in parallel proceedings brought against six water and sewerage companies (WaSCs).[2] The PCR alleged that the six WaSCs had been under-reporting the number of pollution incidents on their respective networks, which led to them charging customers higher prices than they otherwise would have been permitted to charge. In this significant decision, the CAT refused to certify the PCR’s claims on the basis that they were excluded by section 18(8) of the Water Industry Act 1991 (WIA 1991).

This is the first set of environmental claims brought under the UK’s collective proceedings regime and an example of the non-traditional types of claims that have more recently emerged – seeking to take advantage of the opt-out nature of the regime. It is also one of only a handful of cases in which the CAT has declined certification. The judgment is important for its consideration of claims that arise from an alleged or actual breach of obligations under the WIA 1991 (particularly a WaSC’s conditions of appointment), and may also encourage proposed defendants subject to other (complex) regulatory regimes to consider whether any other “exclusions” of a similar nature may exist.

Our Disputes and Investigations team has prepared a detailed briefing on this development, which covers: the legal framework; a summary of the claims and arguments from the WaSCs; and the CAT’s judgment and its implications. 

Slaughter and May acts for United Utilities in these proceedings.

[1]Water Cases (1603; 1628-1631; 1635) - Judgment (Certification) 07 March 2025

[2] The six WaSCs are (1) Anglian Water (2) Northumbrian Water (3) Severn Trent (4) Thames Water (5) United Utilities and (6) Yorkshire Water.