Competition enforcement in the UK carries serious consequences: penalties of up to 10% of worldwide turnover, director disqualification, and follow-on damages claims that can dwarf the original fine. Enforcement runs through the Competition Act 1998, appeals go to the Competition Appeal Tribunal, and private claims, including opt-out collective actions, are a fast-growing risk. We advise businesses on their exposure, on responding to a CMA or sector-regulator investigation, and on managing the litigation risk that follows an infringement finding, coordinating with specialist litigation counsel where proceedings are brought.

The regulatory framework

The Competition Act 1998 contains two prohibitions: the Chapter I prohibition of anti-competitive agreements (section 2) and the Chapter II prohibition of abuse of a dominant position (section 18). The CMA, and the sector regulators exercising concurrent powers, can open an investigation on reasonable grounds for suspecting a breach, using wide powers to compel documents, enter premises and conduct interviews. A firm found to have infringed faces a penalty of up to 10% of its worldwide turnover, set by a structured methodology, and its directors risk a competition disqualification order of up to fifteen years where their conduct makes them unfit.

Infringement and penalty decisions can be appealed to the Competition Appeal Tribunal, which reviews Competition Act decisions on a full-merits standard rather than mere judicial review. Enforcement of the digital markets regime works differently: penalties for breach of a conduct requirement or a pro-competition intervention under the Digital Markets, Competition and Consumers Act 2024 are reviewed by the Tribunal on a judicial review standard, a deliberately lighter touch than the full-merits appeal available under the Competition Act. Dishonest participation in a cartel is also a criminal offence carrying up to five years’ imprisonment, prosecuted separately from the civil regime.

What is the risk of follow-on and collective damages claims?

An infringement finding is often only the beginning of a business’s exposure. Any person who has suffered loss can bring a follow-on damages claim before the Competition Appeal Tribunal, which is bound by the infringement finding. Since the Consumer Rights Act 2015, the Tribunal can also hear opt-out collective proceedings, in which a certified representative brings a claim on behalf of an entire class of consumers or businesses without each member having to opt in. These collective actions have grown quickly, and several of the largest are against digital platforms. For any business exposed to an infringement finding, the damages risk, and the reputational exposure of a class action, can exceed the regulatory penalty.

Exposure	What it involves	Where it is decided
Regulatory penalty	Up to 10% of worldwide turnover for a breach	CMA or a concurrent sector regulator
Director disqualification	Disqualification order of up to fifteen years	Court, on CMA application
Appeal	Full-merits challenge to an infringement or penalty	Competition Appeal Tribunal
Follow-on and collective claims	Damages, including opt-out class actions	Competition Appeal Tribunal

Why competition enforcement matters for your business

The exposure is rarely a single fine. It is a chain of consequences: an investigation that consumes management time and requires careful handling of compelled evidence, a penalty set against worldwide turnover, personal risk for directors, an appeal that turns on the full merits, and damages claims that can follow for years. In regulated sectors, the picture is complicated further by concurrency, because a sector regulator such as Ofcom, the FCA or the Payment Systems Regulator may investigate instead of, or alongside, the CMA. The most valuable advice comes before any of this: competition compliance that keeps a business out of trouble, and, where an investigation does begin, a clear-eyed assessment of exposure and options at the earliest stage. We advise on that risk and coordinate with specialist litigation counsel where proceedings are brought or defended.

How we work

We work with clients in three ways: as direct legal advisers on a specific question, as specialist co-counsel alongside a competition or corporate team, and as fractional general counsel on a retained basis. Rob Bratby currently holds four fractional General Counsel appointments, at The One Touch Switching Company, TelXL, Core Communication and the UK Payments Initiative, giving direct insight into how businesses manage regulatory risk and respond to investigations. A one-year secondment to Oftel adds first-hand experience of how a regulator builds and runs a case. Where a matter involves personal data, we address it through our data protection practice.

Frequently asked questions about competition enforcement

What penalties can the CMA impose?

For a breach of the Competition Act 1998, up to 10% of the undertaking’s worldwide turnover, set by a structured penalty methodology. Directors can face a competition disqualification order of up to fifteen years, and dishonest cartel conduct is a separate criminal offence. Penalties for breach of the digital markets regime are set under the DMCC Act 2024.

Can a CMA decision be appealed?

Yes. Infringement and penalty decisions under the Competition Act 1998 can be appealed to the Competition Appeal Tribunal, which reviews them on a full-merits standard. Decisions under the digital markets regime are reviewed by the Tribunal on a judicial review standard, which is more deferential to the CMA.

What is an opt-out collective action?

It is a class action before the Competition Appeal Tribunal in which a certified representative claims damages on behalf of an entire class, so class members are included unless they opt out. Introduced by the Consumer Rights Act 2015, these actions have grown rapidly and several of the largest target digital platforms.

Could a sector regulator investigate instead of the CMA?

Yes. In regulated sectors, Ofcom, the FCA, the Payment Systems Regulator and others hold concurrent Competition Act powers and may take a case instead of, or in coordination with, the CMA. Which authority acts is decided under the concurrency arrangements, and it affects how an investigation is run.

What is leniency and how does it work?

Leniency is the route by which the first participant in a cartel to report it to the CMA and cooperate fully can secure immunity from financial penalties, with reduced penalties for later applicants. It is governed by the CMA’s leniency guidance rather than set out in detail in statute, and a successful application can also protect individuals from the criminal cartel offence and from director disqualification. Because immunity generally goes only to the first to come forward, the decision whether and when to apply is time-critical and needs early specialist advice.

Does an infringement finding automatically mean I owe damages?

Not automatically, but it opens the door. A binding infringement finding lets any person who suffered loss bring a follow-on damages claim before the Competition Appeal Tribunal, which is bound by the finding, so the case turns on causation and the amount of loss rather than on liability. A claim can be brought individually or as part of an opt-out collective action, which is why damages exposure often outlasts and outweighs the original penalty.

Also see

Explore our related Digital Regulation pages on Concurrent Competition Powers, SMS Designation and Conduct Requirements, Market Investigations and Studies and Merger Control in Digital Markets, or return to the Digital Regulation hub. The regime intersects with our work in Telecoms Regulation, Payments Regulation and Data Protection. For commentary on current developments, see our Insights.