The civil justice overriding objective of justice and efficiency is a general concept that the courts must make operable in practice. The court supervises the pre-trial preparation and management of litigation and gives pre-trial directions about the conduct of the trial. Practice directions have become a substantial source of discretionary procedural law. They muststill be limited to practice and procedure, not substantive law. This article examines the function of practice directions of the scope deployed in implementing the overriding objective and whether they are limited to matters of procedure. In jurisdictions that lack statutory authority for practice directions, the court asserts an inherent jurisdiction. The detail of practice directions gives them the character of a legislative instrument. This prompts the question whether the judges are performing a legislative function in issuing them.