Digital Platform Follow-on Litigation: Brexit Binding Effect and the DMCCA 2024 Trajectory
In short: Digital platform follow-on litigation in the UK pivots on a date many readers know as “full Brexit”. At 11pm on 31 December 2020 the UK formally left the EU competition regime; lawyers call that moment “IP completion day”. Section 58A of the Competition Act 1998, recast by the Brexit statutory instruments SI 2019/93 and SI 2020/1343, draws the line at that date. European Commission infringement decisions made before IP completion day remain binding on UK courts and the Competition Appeal Tribunal. Later Commission decisions bind UK courts only where the Commission was already handling the case at the end of the transition period. The Digital Markets, Competition and Consumers Act 2024 now adds a separate UK enforcement track.
The Stage 1 trial in the consolidated Google Shopping follow-on damages proceedings before the Competition Appeal Tribunal is listed to begin on 22 June 2026, with a time estimate of five weeks and one week in reserve. These are among the most prominent digital platform follow-on litigation proceedings currently before a UK tribunal. They put a spotlight on three rules that practitioners advising on competition damages and digital regulation should hold clearly in mind. The first is the post-Brexit form of section 58A of the Competition Act 1998, which decides when an infringement decision is binding on UK courts and the Tribunal in a follow-on damages claim. The second is the way two Brexit-era statutory instruments, SI 2019/93 and SI 2020/1343, drew the line at the end of the transition period (the moment commonly known as “full Brexit”, and as “IP completion day” in the legal drafting), which took effect at 11pm on 31 December 2020. The third is the new digital markets enforcement regime under Part 1 of the Digital Markets, Competition and Consumers Act 2024, which is starting to produce its first designations and commitments.
The Commission Decision and the Route to a UK Damages Trial
On 27 June 2017, the European Commission issued Decision AT.39740, finding that Google had abused its dominant position in general internet search by favouring its own comparison shopping service over competing comparison shopping services in search results from 2008 onwards. The Commission imposed a fine of €2.42 billion. Google appealed. The General Court dismissed the appeal in Case T-612/17 on 10 November 2021, and the Court of Justice of the European Union, sitting as a Grand Chamber, dismissed a further appeal in Case C-48/22 P on 10 September 2024. The infringement finding is now settled EU law.
UK comparison shopping services filed follow-on damages claims before the Tribunal between 2021 and 2024. The proceedings consolidate four cases under case numbers 1424/5/7/21, 1589/5/7/23, 1596/5/7/23 and 1636/5/7/24. One of the four claimant groups settled in February 2026, leaving three claimant groups before the Tribunal. Stage 1 of the trial is listed for 22 June 2026.
Section 58A After IP Completion Day
The status of the Commission’s 2017 decision in UK follow-on damages proceedings turns on section 58A of the Competition Act 1998. The current section binds the court and the Tribunal to an infringement decision once it has become final, and defines an infringement decision for that purpose by reference to section 47A(6).
Before IP completion day, section 58A(4) extended the binding effect to relevant Commission decisions. That subsection was omitted by regulation 20 of the Competition (Amendment etc.) (EU Exit) Regulations 2019 (SI 2019/93). The omission, together with consequential amendments across the Competition Act 1998 and the Enterprise Act 2002, was timed to take effect on IP completion day (31 December 2020), the original “exit day” references in the 2019 Regulations having been replaced with “IP completion day” by the Competition (Amendment etc.) (EU Exit) Regulations 2020 (SI 2020/1343).
The transitional and saving provisions in Schedule 4 to SI 2019/93, as amended by SI 2020/1343, preserve the binding effect of European Commission infringement decisions made before IP completion day in respect of conduct occurring before that date. The 2020 Regulations align with Article 92 of the EU Withdrawal Agreement, which lets the European Commission finish work it had already started on a case at the end of the transition period. Where the Commission issues an infringement decision in such an already-running case after IP completion day, that decision can still found a follow-on damages claim in the UK. Decisions issued by the Commission in cases opened after IP completion day do not attract section 58A binding effect.
Decision AT.39740, made on 27 June 2017, sits squarely within the pre-IP completion day window and therefore retains binding effect for the purposes of UK follow-on damages claims arising out of the conduct it addressed. What the binding effect mechanism does not resolve is the live legal terrain at trial: the relevant counterfactual, the geographic and product market scope of the abuse on UK national markets, causation and quantum. Those questions remain open and will be addressed at the Stage 1 trial and at later stages of the proceedings.
The Stage 1 Trial and the Recent Scope Ruling
On 13 January 2026, in Kelkoo.com (UK) Limited & Others v Google UK Limited & Others [2026] CAT 3, the Tribunal ruled on the scope of the Stage 1 trial. The order before the Tribunal had been settled at an earlier case management conference and identified, alongside the questions of dominance and abuse, a counterfactual analysis covering the full relevant period addressed by the claims. An application was made in late 2025 to vary that scope by removing part of the counterfactual analysis from Stage 1. The Tribunal refused that application and confirmed the existing scope of the Stage 1 trial.
For practitioners advising on digital platform follow-on litigation, the procedural significance of the ruling lies in the way that case management commitments are taken to operate in complex damages litigation: once the parameters of a phased trial have been settled, an application to vary them late in the timetable will be assessed against the case management history and the proximity of trial. That is a procedural observation, not a comment on the substantive merits of the proceedings, which remain to be argued and decided.
The DMCCA 2024 Sits Alongside the Section 58A Regime
The Google Shopping damages claims run under the pre-DMCCA regime, but the Digital Markets, Competition and Consumers Act 2024 (DMCCA 2024) is starting to shape the landscape for digital platform regulation in the UK. Part 1 of the DMCCA 2024 came into force on 1 January 2025. The Digital Markets Unit within the CMA designated Google and Apple as having strategic market status (SMS) in respect of their mobile platforms on 22 October 2025, and the first commitments under the regime were accepted on 1 April 2026. We discussed those commitments in our earlier piece on the first DMCCA 2024 commitments from Apple and Google.
Commitments accepted under the DMCCA 2024 are not infringement decisions within section 47A(6) of the Competition Act 1998. They do not in themselves generate follow-on damages liability. The DMCCA 2024 and the Competition Act 1998 are nevertheless not mutually exclusive. Where an SMS-designated firm receives a Chapter II infringement decision from the CMA in respect of the same conduct, that decision attracts section 58A binding effect in the same way as any other UK infringement decision. Practitioners advising digital platform operators will want to track the SMS investigation pipeline alongside the existing Chapter II workstreams.
Relevance for Telecoms Operators
Although the Google Shopping proceedings concern comparison shopping services, the structural points reach telecoms operators directly. Telecoms businesses that depend on search placement, advertising infrastructure or app store distribution sit in the same digital ecosystem that the Stage 1 trial will examine. Ofcom holds concurrent powers with the CMA under the Competition Act 1998 in respect of electronic communications networks and services, and an Ofcom infringement decision in that sector attracts section 58A binding effect in follow-on proceedings on the same footing as a CMA decision.
As we noted in our analysis of the proposed EU Merger Guidelines and their implications for telecoms, the convergence of digital and physical infrastructure has placed competition due diligence on platform conduct firmly within the scope of standard transaction legal advice. The post-Brexit binding effect regime, the scope of follow-on damages claims and the DMCCA 2024 enforcement pipeline are part of the legal due diligence landscape for operators and their advisers. For support on transaction risk assessments that involve digital platform competition exposure, see our deal structuring and negotiation page.
Viewpoint
The Brexit transitional binding effect regime is rarely the subject of practitioner attention in its own right. It tends to be folded into broader Brexit narratives. The Google Shopping proceedings are a useful reminder that the regime is doing real work: it allocates which European Commission decisions UK courts and the Tribunal must accept as binding, which fall outside that mechanism, and which sit in the limited continued competence pathway under Article 92 of the Withdrawal Agreement. Any practitioner advising on follow-on damages exposure in respect of conduct that straddles IP completion day needs to walk through that allocation step with care, since it determines the evidential starting point for any UK proceedings.
The DMCCA 2024 trajectory adds a forward-looking dimension. The Google Shopping timeline runs from conduct in 2008 through a 2017 decision, EU appellate proceedings concluded in 2024 and a UK damages trial in 2026. Quantum in digital platform follow-on litigation accumulates over years, and the trajectory of UK enforcement under the DMCCA 2024, while still at an early stage, points toward similar long timelines for any future follow-on damages exposure. Compliance investment now, integrated into existing competition law programmes, is proportionate to that exposure profile.
Rob Bratby advises digital platform operators, comparison shopping services and telecoms operators on competition law compliance and follow-on damages risk. For specific advice on digital platform follow-on litigation exposure or regulatory due diligence in the context of a transaction, contact Rob at rob@bratby.law or visit the contact page.
