At the heart of the topic of this article is a tension between, on the one hand, the principles of efficient enforcement of competition law, and on the other hand, the idea of due process which includes respect of the rights of defence and equality of arms. Added to this tension between competing objectives is a potential conflict over the interpretation of rights by the Court of Justice of the European Union (CJEU) and the European Court of Human Rights (ECtHR): obviously, the judges belonging to each institution may have their own idea about which court should have the last say in matters concerning fundamental rights. It is against this background that the ECHR’s role in the EU legal order must be appraised, i.e. not one set in stone, but one which has shown interesting evolutions ever since the signing of the Treaty of Rome until what is now the European Union (EU).