CAT’s rejection of proposed competition claims against water companies upheld on appeal

06/03/26

In December 2023, Professor Carolyn Robert brought applications for collective proceedings orders against six water and sewerage undertakers (the “PDs”) alleging that, in breach of section 18 of the Competition Act 1998, the PDs had abused a dominant position by under-reporting the number of pollution incidents that occurred on their sewerage networks and, through the operation of the relevant regulatory price control regime, had thereby recovered greater revenues from their household customers than they would have had they correctly reported the number of pollution incidents.

In a judgment of 7 March 2025, the Tribunal held that the proposed claims were excluded by section 18(8) of the Water Industry Act 1991 because breach of the PDs’ conditions of appointment as water and sewerage undertakers was an essential ingredient of the proposed claims for beach of section 18 of the Competition Act 1998. The proposed private law claims could not therefore be brought; enforcement of compliance with the PDs’ appointment conditions rests primarily with the regulator, Ofwat.

Professor Roberts appealed against the Tribunal’s decision.

In its judgment of 5 March 2026, the Court of Appeal (Vos and Falk LJJ) upheld the Tribunal’s decision, albeit on slightly different grounds. Zacaroli LJ dissented.

The judgment can be accessed here.