On 19 February 2020, in the latest episode to date of the long-running Micula saga, the United Kingdom (UK) Supreme Court gave its green light to the enforcement in the (UK) of the award obtained by the Micula brothers against Romania (Award) under the 2002 Sweden-Romania bilateral investment treaty (BIT), despite the fact that the question of whether this Award constitutes state aid prohibited under EU law was pending before the Court of Justice of the European Union (CJEU). The Supreme Court ruled that the UK enforcement obligations under the ICSID Convention could not be affected by the EU duty of sincere cooperation, as the UK’s ratification of the ICSID Convention preceded its accession to the EU. The UK Supreme Court judgment, and the prior main episodes of the Micula saga in the framework of the ICSID, EU state aid and enforcement proceedings, offer a great opportunity to explore the increasingly tumultuous relationship between investment arbitration and EU (competition) law, in particular the compatibility of intra- EU investment arbitrations under the ICSID Convention with EU law and the coexistence of selective protections under international investment law with EU state aid law.