King's College London

The protection of legitimate expectations has become the ‘dominant’ element of the fair and equitable treatment (FET) standard in the practice of investment tribunals. While its precise content and scope of application varies, the principle of legitimate expectations is found in many legal systems including in English and European Union (EU) law. Using English and EU law as a benchmark, the aim of this contribution is to explore the role played by the ‘public interest’ in the protection of legitimate expectations in investment arbitration. Focusing on the many recent decisions rendered in the context of the clean energy arbitrations brought in the last ten years in particular against Spain and Italy, I argue that, in contrast to the way the doctrine has been developed in English and EU law, many (but not all) investment tribunals applying the doctrine of legitimate expectations have attributed little or no relevance to the public interest. This in turn raises significant concerns with regard to the authority and legitimacy of investment treaty law and arbitration.