The Ruling
On 5 August 2026, the Competition Appeal Tribunal (CAT) certified a collective proceedings order against Alphabet, Google LLC and four Google subsidiaries, allowing a £5 billion claim brought by Or Brook Class Representative Limited to proceed to trial (case 1720/7/7/25, neutral citation [2026] CAT 65). The claim, filed by competition-law academic Dr Or Brook under section 47B of the Competition Act 1998, alleges Google abused its dominance in general search to inflate search advertising prices for UK businesses between 1 January 2011 and 15 April 2025 — a class period spanning more than fourteen years. Roughly 880,000 UK-domiciled advertisers are automatically included in the class unless they opt out, a mechanism the tribunal chose over Google's preferred opt-in structure after a three-judge panel (Mr Justice Meade, John Davies and Robert Herga) found the company's objections amounted to what the judgment called a "nit-picking, negative approach." This is a certification decision, not a finding of liability — Google has not been found to have broken the law, and the case must still be proven at trial.
Why Opt-Out Beats Opt-In Here
Google argued that direct distribution to nearly 900,000 businesses would be impracticable given incomplete advertiser records and the involvement of media-buying agencies, and pointed to precedent (the Gutmann litigation) where opt-in take-up ran below 1%. The tribunal rejected the analogy: distributing money to identified account holders, it reasoned, is a fundamentally different exercise from persuading class members to affirmatively join uncertain litigation, and "effective, direct distribution to specifically identified individual class members of an aggregate award far in excess of 1 per cent may reasonably be expected." The panel also noted opt-in would be slower and complicate case management alongside a parallel consumer claim, Stopford v Alphabet. That reasoning is sound as far as it goes — the UK's opt-out collective proceedings regime, introduced by the Consumer Rights Act 2015 specifically to solve the standing problem for dispersed commercial claimants, exists precisely because rational-apathy means most wronged businesses never self-select into a claim. An opt-in threshold effectively lets a dominant defendant cap its own exposure by exploiting claimant inertia, which is not really "choice" in any meaningful sense.
The Steelman for Caution
It is worth taking Google's underlying concern seriously rather than dismissing it as delay tactics. Opt-out certification exposes a defendant to aggregate liability calculated by a claimant-side expert economist before the underlying conduct has been adjudicated, and it does so in a case covering fourteen years of a market that changed enormously — Google's search advertising auction, quality scores and ad formats in 2011 bear little resemblance to those of 2025. A single certified class covering that entire span risks flattening real differences in market conditions and harm across the period into one damages model, and the size of the headline number (£5bn) itself becomes a settlement-pressure figure independent of the claim's merits. English and Welsh courts and tribunals have historically been more claimant-cautious than the US class-action system for good reason: aggregate litigation can incentivise settlement of weak claims simply to avoid catastrophic tail risk. That is a legitimate proportionality concern, not merely corporate reluctance to face scrutiny.
The Bigger Pattern: A Second Front Opens
What makes this certification more than a single large lawsuit is timing. The CMA designated Google with Strategic Market Status (SMS) in general search and search advertising on 10 October 2025 — the first designation under the Digital Markets, Competition and Consumers Act 2024 — after finding Google accounts for over 90% of UK search queries. That designation has already produced conduct requirements on publisher terms and fair ranking, imposed in June 2026. The CAT claim now runs on a separate, private-litigation track that does not depend on the CMA's regulatory timeline or its remedies being adequate. For a company with Google's UK footprint, that means simultaneous exposure to forward-looking behavioural conduct requirements from a regulator and backward-looking financial liability from a claimant class — two enforcement mechanisms operating on different legal tests, different timelines and different theories of harm, both grounded in the same underlying dominance finding.
What Actually Follows
The sensible middle position is not to root against either track but to insist each stays within its lane. Regulatory conduct requirements under the DMCC Act are the right tool for prospective, structural fixes to how search and search-advertising markets function going forward — they can be tailored, monitored and adjusted. Collective proceedings are the right tool for compensating identifiable past harm, but only if the trial that follows this certification actually tests the underlying abuse allegation with rigour, rather than the size of the certified class becoming a substitute for proving it. The CAT was correct that opt-in would have hollowed out the claim's practical value; it will now matter far more whether the substantive abuse case holds up at trial than whether procedure favoured claimants at the certification stage.