Update
The Supreme Court has granted permission for proposed class representative Professor Carolyn Roberts to appeal against the Court of Appeal’s decision not to allow an environmental claim against six water and sewerage undertakings to proceed under the Competition Appeal Tribunal’s opt-out collective proceedings regime.
Background
In March 2026, the Court of Appeal upheld the 2025 decision of the Competition Appeal Tribunal (CAT) not to allow an environmental claim against six water and sewerage undertakings, regarding the reporting of pollution incidents to proceed under the CAT’s opt-out collective proceedings regime for breaches of competition law.
This case has been closely watched, as it is the first time the CAT’s collective proceedings regime, which is currently the only forum for bringing US style opt-out claims in England and Wales, has been used to try to bring an environmental claim, arguably trying to extend the scope of the opt-out regime beyond more traditional competition cases.
While the CAT and the Court of Appeal declined to certify the claim, the first step in the collective proceedings regime, this was not because they did not consider that the acts complained of amounted to a potential abuse of dominance in breach of competition law, but because the remedies for any inaccurate reporting were limited to those set out in the Water Industry Act 1991 (WIA). This is also the question for the Supreme Court: Is a cause of action under the Competition Act excluded by the WIA?
We could therefore see further attempts to broaden the scope of collective proceedings brought in the CAT to non-traditional competition claims in this way. While the Law Commission has recently announced it is considering a potential opt-out class actions regime for consumer claims more generally (see our update here: Update: Law Commission Considering a New Consumer Class Actions Regime – What You Need To Know | Insights | Squire Patton Boggs), any such regime outside of the CAT is likely to be some way off.
What is the claim?
Professor Carolyn Roberts, an environmental science and water management specialist, seeks to act as class representative to bring claims against six English water and sewerage companies, seeking damages on an “opt-out” basis on behalf of millions of their household customers. The claims are understood to backed by up to £31 million of litigation funding. Separate claims were issued against each water company, but the CAT directed that they be heard together. The claims allege that the water companies had under-reported the number of pollution incidents, which under the established pricing regime allowed them to charge higher prices to their customers. The claims seek damages comprising the difference between the amounts customers actually paid, and the lower amounts they say should have been charged if pollution incidents had been properly reported. Crucially, given the CAT’s collective proceedings regime is limited to breaches of competition law, this is alleged to constitute an abuse of a dominant position contrary to s.18 Competition Act 1998.
Following a three day certification hearing in 2025, the CAT found that as the damages claim was tied to under-reporting (if established) being in contravention of a relevant condition of appointment under the WIA, the statutory exclusion of “other remedies” in s.18(8) WIA operated to exclude these damages claim for abuse of dominance.
While not strictly necessary to do so, the CAT’s judgment went on to consider whether the alleged conduct was outside the scope of competition law and the CAT expressly said that if the claims were not so excluded by the WIA, it would have granted collective proceedings orders (CPOs) in each set of proceedings.
The CAT’s refusal to grant the CPOs therefore turned on the wording of the WIA, rather than any finding that this was not a competition law claim within the scope of the CAT’s collective proceedings regime.
The appeals
Professor Roberts first appealed to the Court of Appeal. The question before it was whether the CAT was correct as a matter of law to find that the claims were excluded by the WIA. In March 2026, it said that the key question was whether Professor Roberts was claiming remedies that were available only by virtue of the relevant acts (the alleged inaccurate or under-reporting) constituting a contravention of the WIA. It found that this was an essential ingredient of her claims, and so dismissed the appeal, though there was a dissenting judgment from Zacaroli LJ, who did not think the claim could only be maintained by relying on the reporting obligations in the licence conditions.
The Supreme Court has now granted permission to appeal this finding.
