In its long awaited ruling on the Eurotunnel case, the Competition Appeal Tribunal has delivered a wide-ranging judgment dealing with almost the whole of the legal framework within which the Competition Commission considers mergers. Two aspects of the judgment are of particular importance. First, the judgment gives detailed consideration to the concept of an “enterprise”, and how that concept is to be distinguished from an asset purchase. Secondly, and of even greater importance, the Tribunal considered whether the Commission’s procedures, and its management of confidential information, require modification in light of recent decisions of the Supreme Court on closed procedures and the approach taken in EU law (the principle of “access to the file”). In summary, the Tribunal quashed the CC’s finding that it had jurisdiction to consider the transaction and remitted that question to the CC. However, the Tribunal rejected the wide ranging criticisms of the CC’s procedures and found that there was no breach of natural justice in the particular case. The Tribunal also rejected grounds of review concerned with the CC’s assessment of competitive effects and remedies.