On 19 September 2007, the European Commission put forward a package of measures intended to facilitate the further opening of EU electricity and gas markets to competition. Arguably, the most controversial of the measures proposed are those concerning the requirement for the "unbundling" or separation of electricity and gas transmission networks from supply and/or generation activities. This would effectively mean that energy networks would no longer be affiliated to part of a group which is active in supply, generation and production (although the new rules would not prevent the holding of minority, non-controlling interests). However, by way of derogation and of compromise for those to whom this solution is unacceptable, network assets would remain in the hands of vertically-integrated groups provided that network activities are regulated and controlled by an Independent Systems Operator. The Commission has also proposed rules governing ownership and control of transmission systems by non-EU companies to ensure that the objectives of independence are respected.