Contributor(s): Margrethe Vestager | National authorities (NCAs) and national courts are empowered to apply the EU competition rules together with the Commission. Since 2004, the Commission and the NCAs together have adopted almost 1,000 decisions in antitrust cases – 85% by the NCAs. Joint action within the European Competition Network means more effective enforcement and more deterrence. However, despite common substantive rules, national authorities must rely on national procedural powers when applying EU law. Where those powers are not fully developed, both the NCAs' effectiveness as enforcers and the level playing field in the single market risk being undermined. The time is therefore ripe to consider boosting the enforcement powers of NCAs. Margrethe Vestager (@vestager) is European Commissioner for Competition. She is a former Danish Minister for Economic Affairs and the Interior and former Deputy Prime Minister of Denmark. The LSE European Institute (@LSEEI) was established in 1991 as a dedicated centre for the interdisciplinary study of processes of integration and fragmentation within Europe. In the most recent national Research Excellence Framework (REF 2014) the Institute was ranked first for research in its sector.