Two law firms — Harcus Parker and Hausfeld — have filed an application at the UK Competition Appeal Tribunal seeking a group claim against Visa and Mastercard worth an estimated £5bn. The claim covers multilateral interchange fees charged to UK businesses on debit, credit, and prepaid card transactions from October 2020 to 2026. The core allegation: the duopoly's fee-setting power, absent meaningful competition, has left businesses paying more than a functioning market would produce. The mechanism is straightforward. Every time a customer taps a card, the business pays an interchange fee set by Visa or Mastercard, routed through their acquiring bank. Businesses don't negotiate these fees. They don't choose between competing fee schedules. They accept the rate or stop accepting cards — which in 2025 Britain means stop doing business. The lawsuit argues this isn't pricing; it's rent extraction from a captive market. The claim is being led by Stephen Allen, a former travel executive who has pursued Visa and Mastercard through multiple group actions since 2021. Funding comes from Bench Walk Advisors, a litigation finance firm. If the application succeeds, roughly 1 million UK businesses, organisations, and charities with under £100m in revenue will be automatically included unless they opt out. Larger businesses must opt in. Individual claims could range from several thousand pounds to tens of millions. Mastercard's response is revealing in what it concedes and what it fights. The company calls the claim "speculative" and part of a "growing trend of opportunistic funder-backed litigation." It points to proposed UK government reforms to opt-out class actions currently out for consultation this summer, essentially arguing the legal mechanism being used against it should be curtailed. Visa offers the standard institutional defense: interchange is "a critical component to maintaining a secure digital payments ecosystem." The US precedent is instructive but sobering. Visa and Mastercard last year settled a US class action over ATM access fees for a combined $167.5m — from a lawsuit originally filed in 2011. Thirteen years from filing to settlement. The UK claim, if it follows a similar trajectory, could stretch well into the 2030s. Litigation finance firms like Bench Walk profit from exactly this timeline: they front costs, take a cut of any settlement, and the actual businesses see compensation years or decades after the harm. The structural problem litigation cannot touch is the duopoly itself. Visa and Mastercard together process the overwhelming majority of UK card transactions. No lawsuit changes that. Even a £5bn settlement, spread across a million businesses and six years of overcharging, amounts to a cost of doing business — not a structural remedy. The fees resume the day after settlement. The real question is whether UK regulators or policymakers will impose interchange fee caps, mandate interoperability between payment networks, or create conditions for genuine competition on the rails themselves. Mastercard's citation of the UK government's proposed opt-out class action reforms deserves attention. If the government narrows the mechanism by which these claims can be brought, it removes one of the few tools available to fragmented, individually powerless businesses facing concentrated market power. The consultation document is live this summer. Whether it protects consumers or protects incumbents will say more about the UK's competitive environment than any court ruling.
