The Competition Commission is an independent body responsible for investigating mergers, market shares and conditions and the regulation of UK companies.

The Commission replaced the Monopolies and Mergers Commission on April 1 1999.

The Commission has no authority to commence investigations on its own, an inquiry commences following the referal of a particular case to the Commission, most often by the Office of Fair Trading (OFT). Inquries may also result from referals from the Secretary of State for Trade and Industry (e.g. Morrison bid for Safeway supermarkets) or independent regulators. For mergers the Commission will be asked to investigate if the takeover target has a turnover above a certain threshold or if the resulting company would have 25% or more of a market, i.e. a monopoly position.