Big CAT Watch

The UK Competition Appeal Tribunal (the CAT) is dealing with some enormous pieces of litigation as part of its competition collective action regime. 

These big claims have become the pride of the CAT and the main event in UK collective redress. But developments in collective proceedings can happen quickly and quietly and keeping track of them can feel like herding cats.

Big CAT Watch is our platform containing data and analysis on UK collective proceedings. Our Big CAT Watch visualisations chew through the complexity and show you what you need to know about UK collective proceedings.

The information in this analysis is updated each month. It was last updated on 5 May 2026. The information is taken from documents published on the CAT’s website, so new applications will not be included until the CAT publishes them. We note that Linklaters acts in several of the proceedings covered in this analysis.

The Big CAT Watch charts below show:

• The certification status of collective proceedings applications
• Whether applications have been brought on an opt-in or opt-out basis
• Whether they are standalone or follow-on from a regulatory decision
• The infringement type alleged
• The industrial sector which the claim concerns
• The eventual outcomes of collective proceedings

Future Developments

Changes are moving quickly through the Big CAT grasslands:

• In August 2025, the UK Government’s Department for Business & Trade began a review of the opt-out collective proceedings regime. In its call for evidence, the Government said that it was seeking to find the right balance between achieving redress for consumers and limiting the burden of the collective proceedings regime on business. Our response to the call for evidence is available here.
• In December 2025 the Ministry of Justice announced plans to introduce legislation to reverse the Supreme Court’s decision in PACCAR. That decision currently prohibits litigation funders’ returns from being calculated as a percentage of damages recovered (the result being that returns currently have to be calculated as a multiple of capital invested instead).
• In April 2026, the Law Commission announced that it had launched a new project to consider the potential introduction of a consumer class actions regime. The Law Commission has said that it intends to start work on the project during autumn 2026 and, in advance of that, has invited views from stakeholders to be submitted through an initial scoping questionnaire