This chapter provides a deep dive into UK company law, assessing the common law before the changes to the Companies Act enacted in 2006. It finds that prior to 2006, the judiciary provided directors with a significant amount of discretion to make even profit-sacrificing actions if they benefited the company as a whole, widely reflecting the entity theory of companies. Corporate governance reviews, from the Cadbury Report onwards, did not reflect this common law approach. A detailed examination of the work of the Company Law Review Steering Group illustrates that the changes codified in s172 of the Companies Act 2006 actually entrenched a shareholder primacy approach to company law that previously was not dominant in English common law. This development could have negative impacts for the climate, although the relationship between s172 and the prior common law interpretation of directors’ duties remains unclear. Post-2006 cases are also assessed, and an overview of where climate liability could arise for directors under the 2006 Act is provided.