who are the major players?

ITV is the major commercial public service TV network in the United Kingdom. Launched in 1955 under the auspices of the Independent Television Authority (ITA) to provide competition to the BBC, it is also the oldest commercial network in the UK. Since the passing of the Broadcasting Act 1990, its legal name has been Channel 3, the number 3 having no real meaning other than to distinguish it from BBC One, BBC Two and Channel 4. In part, the number 3 was assigned as televisions would usually be tuned so that the regional ITV station would be on the third button, the other stations being allocated to that of the number their name contained.
ITV is to be distinguished from ITV plc, the company that resulted from the merger of Granada plc and Carlton Communications in 2004 and which is the parent of ITV Broadcasting Limited to whom all of the Channel 3 broadcasting licences in England, Wales, Southern Scotland and the Isle of Man were transferred in November 2008. Similarly ITV1 is the brand used by ITV plc for the Channel 3 service in these areas. Of the companies external to ITV plc, Channel Television uses ITV's branding in the Channel Islands whilst STV and UTV use their own brands in their own respective areas (Northern and Central Scotland and Northern Ireland).

The British Broadcasting Corporation (BBC) is a British public service broadcaster, headquartered at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff. Its main responsibility is to provide public service broadcasting in the United Kingdom, Channel Islands and Isle of Man. The BBC is an autonomous public service broadcaster that operates under a Royal Charter and a Licence and Agreement from the Home Secretary. Within the United Kingdom its work is funded principally by an annual television licence fee, which is charged to all British households, companies and organisations using any type of equipment to record and/or receive live television broadcasts; the level of the fee is set annually by the British Government and agreed by Parliament.
Outside the UK, the BBC World Service has provided services by direct broadcasting and re-transmission contracts by sound radio since the inauguration of the BBC Empire Service in December 1932, and more recently by television and online. Though sharing some of the facilities of the domestic services, particularly for news and current affairs output, the World Service has a separate Managing Director, and its operating costs have historically been funded mainly by direct grants from the British government. These grants were determined independently of the domestic licence fee. A recent spending review has announced plans for the funding for the world service to be drawn from the domestic licence fee.
The Corporation's 'guaranteed' income from the licence fee and the World Service grants are supplemented by profits from commercial operations through a wholly owned subsidiary, BBC Worldwide Ltd. The company's activities include programme- and format-sales, magazines including the Radio Times and book publishing. The BBC also earns additional income from selling certain programme-making services through BBC Studios and Post Production Ltd., formerly BBC Resources Ltd, another wholly owned trading subsidiary of the corporation.
Channel 4 is a British public-service television broadcaster which began working on 2 November 1982. Although largely commercially self-funded, it is ultimately publicly owned; originally a subsidiary of the Independent Broadcasting Authority (IBA), the station is now owned and operated by the Channel Four Television Corporation, a public body established in 1990, coming into operation in 1993. With the conversion of the Wenvoe transmitter in Wales to digital on 31 March 2010, Channel 4 became a UK-wide TV channel for the first time.
The channel was established to provide a fourth television service to the United Kingdom in addition to the television licence-funded BBC's two services and the single commercial broadcasting network, ITV.