Group actions are becoming increasingly significant in the UK, presenting both risks and opportunities for businesses. At Stephenson Harwood, we understand that clients need clear, strategic advice to navigate the complex, technical challenges that group actions present.
Our dedicated team brings together leading commercial litigators and sector specialists. We act for both claimants and defendants in complex, multijurisdictional group claims, including in the High Court, the Competition Appeal Tribunal, the Courts of Justice of the European Union and the English appellate courts. We have extensive experience acting on competition damages claims, securities and shareholder actions, consumer claims, and data protection disputes, amongst other types of group action. We routinely represent corporate clients both as claimants and as defendants.
We have a proven track record in some of the most high-profile group actions currently proceeding in the English courts, including two of the largest claims in the CAT. Our clients benefit from our deep expertise and our innovative approach to managing large-scale claims, and our experience of managing disputes from inception through to trial, as well as on appeal.
Stephenson Harwood has a leading commercial litigation practice with expertise across a broad sweep of commercial and group litigation.’
The Legal 500 UK 2025
We have a strong relationship with litigation funders and insurers and collaborate closely with them when developing and pursuing group actions. We also have excellent relationships with economists, forensic accountancy firms, and barristers' chambers, to ensure that our clients have access to expert assistance, regardless of the nature of the dispute.
Our Services
We have a proven track record in delivering for clients in complex, high-value group actions.
- Merchant Interchange Umbrella Proceedings
We represented almost 2,000 corporate claimants in group claims brought against Visa and Mastercard seeking recovery of losses caused by unlawful Multilateral Interchange Fees set by Visa and Mastercard on every card transaction processed by our clients in the UK and Europe. A trial on liability issues took place over 6 weeks in early 2024, with a judgment finding for the SH claimants on all issues being handed down in June 2025 and a trial on pass-on issues took place over 7 weeks between November 2024 and April 2025. The claims were successfully settled with Mastercard in June 2024 and with Visa in April 2025. - Leading UK Supermarkets, including Marks and Spencer, Aldi, Iceland, Ocado Retail, Asda, Morrisons and Co-op
We act for 7 of the UK's largest supermarket groups (Aldi, Asda, Co-op, Iceland, Marks and Spencer, Morrisons and Ocado) in claims arising from an alleged cartel in the market for farmed Atlantic salmon. The alleged cartel is under investigation by the European Commission, which has issued a Statement of Objections. The claim is estimated to be worth hundreds of millions of pounds. Our clients successfully defended a jurisdiction challenge brought by 6 separate defendant legal teams in March 2025. - Advising Steering Committee in Fraud Action
We are advising the steering committee of a large group fraud action in relation to confidential matters arising from difficulties encountered in the underlying group action, including the withdrawal of funding and how to address adverse cost risks.
We have deep experience in defending a wide variety of group claims.
- Bilateral competition claim
Advising RCI Financial Services Limited in successfully opposing an application for injunctive relief, and striking out claims, which alleged that by refusing to continue to supply a franchisee dealer our client had breached relevant provisions of the Competition Act 1998 and the Unfair Contract Terms Act 1977. - Banking group litigation
Advising a number of European banks on hundreds of proceedings in several jurisdictions arising from multi-billion Euro loan portfolios. Part of this work includes managing group claims in England and another EU Member State relating to NPL portfolios including hundreds of parallel jurisdiction challenges in each jurisdiction and proceedings before the ECJ. The jurisdiction in which the group claims will proceed is of huge substantive and strategic importance. - Representative action
Advising a leading hotel chain on successfully defending a representative action pursuant to CPR r. 19.8 in respect of alleged losses arising from breaches of the Consumer Protection from Unfair Trading Regulations 2008. - Data Group Action
Advising a multi-national technology client in its defence of a cross-border data group action relating to allegations of unlawful sharing of sensitive personal data. - Follow-on group action
Defending follow-on group action litigation for a pensions master trust arising out of the Capita data breach.
Awards and Recognition
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