A lot of ink has been devoted
to Brexit: when (and if) it will happen, under what terms, and what its legal
effects will be. Some have enquired whether Brexit can create an avalanche of
investor-state disputes potentially based on the frustration of the investors’
legitimate expectations. This article takes a step back from the current
volatility of the ongoing negotiations and addresses a bigger policy question,
which has been emerging steadily also in other contexts: what will be the
actual interplay between international, EU and domestic laws for the resolution
of investment disputes after Brexit? To address this question, this article
first examines the Withdrawal Agreement and the new arbitration mechanism that
it establishes. Second, it explores the interaction between international and
domestic laws, in light of the current developments in EU law, especially the Achmea judgment and the Member States’ Declarations on Achmea, as well as implications for the enforceability of arbitral
awards in the UK post-Brexit. The article concludes with the remark that policy
makers need to address the current underlying tensions between the three laws
of international investment; domestic, EU, and international, by paying due
respect to international law.