On 1 May 2004, huge changes were introduced to the way in which EC competition law is enforced. The recent enlargement, with ten new EU Member States, is probably the most important change, because it results in a scale change in the size of the European Union. However, that change has also led to other important changes: a reappraisal of how enforcement is spread across competition authorities in the European Union and an effort to see whether other modernising steps should be taken. Coincidentally, the EC Merger Control Regulation has also been subject to a review mechanism and the related changes to this Regulation also came into force on 1 May 2004. Taking the changes in the order of likely significance to companies, the main changes are: (1) A revised EC Merger Control Regulation came into force after an extensive review of the existing one, bringing a new substantive test.1 (2) The modernising features of Council Regulation 1/20032 came into force, above all with the abolition of notifications to the European Commission (the ‘Commission’) for clearance of agreements. (3) The decentralisation aspects of Council Regulation 1/2003 came into force, above all the shared enforcement of the whole of Article 81 of the EC Treaty (‘EC’) with national competition authorities and national courts, meaning that they can also apply Article 81(3) EC. (4) A further ten countries, including the Czech Republic, joined the European Union,3 bringing new markets and opportunities for competition, an even greater breadth to the European Union and, as noted, a scale change in how the European Union has to be organised
