competition between companies in the UK for the benefit of companies, customers and the economy. All of the CC's inquiries were undertaken following a reference made by another authority, most often the Office of Fair Trading (OFT) (which referred merger and market inquiries), or one of the sector regulators (which could refer markets within their sectoral jurisdictions or make regulatory references in relation to price controls and other licence modifications) or as a result of an appeal from a decision of one of the sector regulators. Mergers Under the Enterprise Act 2002 (the Enterprise Act), the OFT could review mergers to investigate whether there was a realistic prospect that they would lead to a substantial lessening of competition (SLC), unless it obtained undertakings from the merging parties to address its concerns or the market was of insufficient importance. To qualify for investigation by the OFT, a merger needed to meet all three of the following criteria: two or more enterprises must cease to be distinct; the merger must not have taken place already, or must have taken place not more than four months ago; and one of the following must be true: the business being taken over has a turnover in the UK of at least £70 million; or the combined businesses supply (or acquire) at least 25 per cent of a particular product or service in the UK (or in a substantial part of the UK), and the merger results in an increase in the share of supply or consumption. In exceptional cases where public interest issues are raised, the Secretary of State could also refer mergers to the CC. Where an inquiry was referred to the CC for in-depth investigation, the CC had wide-ranging powers to remedy any competition concerns, including preventing a merger from going ahead. It could also require a company to sell off part of its business or take other steps to improve competition. Market investigations The Enterprise Act 2002 enabled the OFT (and the sector regulators) to investigate markets and, if they were concerned that there may be competition problems, to refer those markets to the CC for in-depth investigation. In market investigations the CC had to decide whether any feature or combination of features in a market prevents, restricts or distorts competition, thus constituting an adverse effect on competition (AEC). Before finding out what percentage firms take up, the CC has to 'define