During the late 990s, the European Union decided to fundamentally change the basis for the provision of electricity and gas from a monopolistic to a competitive market framework. This objective was introduced via the first electricity and gas Directives (2), which removed the legal monopolies and partially opened the market to competition by allowing large users to choose their suppliers. Already at that early stage, the Community legislator identified the risk that vertically integrated incumbents could use their monopolies over the transmission networks in order to stifle the emergence of competition in the supply business. Rules were established to mitigate that risk, including the introduction of a Third Party Access regime and some unbundling provisions to ensure that vertically integrated operators would not discriminate against new entrants or create other entry barriers.