This document summarizes recent developments in UK security class actions and their impact on directors and officers (D&O) insurance markets. It notes that shareholder class actions against corporations and their directors have grown significantly in the last 10 years. Key changes to UK law and court procedures have enabled group litigation orders and representative actions, making it easier for shareholders and investors to collectively pursue compensation claims. Major class actions involving companies like Royal Bank of Scotland, Lloyds Bank, and Tesco are discussed, as well as the growing role of third-party litigation funders. The author argues that this changing landscape means D&O insurers can no longer view UK class actions as a solely US issue and will need to reconsider the types and