Channel 4

Channel 4 is a British public-service free-to-air television network headquartered in London, United Kingdom. It began transmission 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 Channel Four Television Corporation, a public corporation of the Department for Digital, Culture, Media and Sport, which was established in 1990 and came into operation in 1993. With the conversion of the Wenvoe transmitter group in Wales to digital terrestrial broadcasting on 31 March 2010, Channel 4 became a UK-wide television channel for the first time.

The channel was established to provide a fourth television service to the United Kingdom in addition to the licence-funded BBC One and BBC Two, and the single commercial broadcasting network ITV.

Conception
Before Channel 4 and S4C, Britain had three terrestrial television services: BBC1, BBC2, and ITV. The Broadcasting Act 1980 began the process of adding a fourth; Channel 4 was formally created, along with its Welsh counterpart, by an Act of Parliament in 1982. After some months of test broadcasts, it began scheduled transmissions on 2 November 1982.

The notion of a second commercial broadcaster in the United Kingdom had been around since the inception of ITV in 1954 and its subsequent launch in 1955; the idea of an "ITV2" (which came in 1998) was long expected and pushed for. Indeed, television sets sold throughout the 1970s and early 1980s had a spare tuning button labelled "ITV/IBA 2". Throughout ITV's history and until Channel 4 finally became a reality, a perennial dialogue existed between the GPO, the government, the ITV companies and other interested parties, concerning the form such an expansion of commercial broadcasting would take. Most likely, politics had the biggest impact in leading to a delay of almost three decades before the second commercial channel became a reality.

One clear benefit of the "late arrival" of the channel was that its frequency allocations at each transmitter had already been arranged in the early 1960s, when the launch of an ITV2 was highly anticipated. This led to very good coverage across most of the country and few problems of interference with other UK-based transmissions; a stark contrast to the problems associated with Channel 5's launch almost 15 years later.

Wales
At the time the fourth service was being considered, a movement in Wales lobbied for the creation of dedicated service that would air Welsh-language programmes, then only catered for at "off peak" times on BBC Wales and HTV. The campaign was taken so seriously by Gwynfor Evans, former president of Plaid Cymru, that he threatened the government with a hunger strike were it not to honour the plans.

The result was that Channel 4 as seen by the rest of the United Kingdom would be replaced in Wales by Sianel Pedwar Cymru (S4C) ("Channel Four Wales"). Operated by a specially created authority, S4C would air programmes in Welsh made by HTV, the BBC and independent companies. Initially limited frequency space meant that Channel 4 could not be broadcast alongside S4C, though some Channel 4 programmes would be aired at less popular times on the Welsh variant; this practice continued until the closure of S4C's analogue transmissions in 2010, at which time S4C became a fully Welsh channel.

Since then, carriage on digital cable, satellite and digital terrestrial has introduced Channel 4 to Welsh homes where it is now universally available.

Public service remit
Channel 4 was established with, and continues to hold, a remit of public service obligations which it must fulfil. The remit changes periodically, as dictated by various broadcasting and communications acts, and is regulated by the various authorities Channel 4 has been answerable to; originally the IBA, then the ITC and now Ofcom.

The preamble of the remit as per the Communications Act 2003 states that:

""The public service remit for Channel 4 is the provision of a broad range of high quality and diverse programming which, in particular:
 * demonstrates innovation, experiment and creativity in the form and content of programmes;
 * appeals to the tastes and interests of a culturally diverse society;
 * makes a significant contribution to meeting the need for the licensed public service channels to include programmes of an educational nature and other programmes of educative value; and
 * exhibits a distinctive character."

The remit also involves an obligation to provide programming for schools, and a substantial amount of programming produced outside of Greater London.

Presentation
Since its launch in 1982, Channel 4 has used the same logo which consists of a stylised numeral "4" made up of nine differently shaped blocks. The logo was designed by Martin Lambie-Nairn and his brother Robinson and was the first channel in the UK to depict an ident made using advanced computer generation (the first electronically generated ident was on BBC Two in 1979, but this was two-dimensional). It was designed in conjunction with Bo Gehring Aviation of Los Angeles and originally depicted the "4" in red, yellow, green, blue and purple. The music accompanying the ident was called "Fourscore" and was composed by David Dundas; it was later released as a single alongside a B-side, "Fourscore Two", although neither reached the UK charts. In November 1992, "Fourscore" was replaced by new music.

In 1996, Channel 4 commissioned Tomato Films to revamp the "4", which resulted in the "Circles" idents showing four white circles forming up transparently over various scenes, with the "4" logo depicted in white in one of the circles.

In 1999, Spin redesigned the logo to feature in a single square which sat on the right-hand side of the screen, whilst various stripes would move along from left to right, often lighting the squared "4" up. Like the "Circles" idents, the stripes would be interspersed with various scenes potentially related to the upcoming programme.

The logo was made three-dimensional again in 2004 when it was depicted in filmed scenes that show the blocks forming the "4" logo for less than a second before the action moves away again.

In 2015, the logo was disassembled completely to allow the blocks to appear as parts of a nature scene, sometimes featuring a strange dancing creature and sometimes being excavated for scientific study, one being studied under a microscope and showing a tardigrade. The second wave of these idents, launched in 2017, depict a giant creature made of the "4" blocks (made to look almost like a person) interacting with everyday life, sometimes shouting the "Fourscore" theme as a foghorn.

All 4
All 4 is a video on demand service from Channel 4, launched in November 2006 as 4oD. The service offers a variety of programmes recently shown on Channel 4, E4, More4 or from their archives, though some programmes and movies are not available due to rights issues.

4-Tel/FourText
Channel 4 originally licensed an ancillary teletext service to provide schedules, programme information and features. The original service was called 4-Tel, and was produced by Intelfax, a company set up especially for the purpose. It was carried in the 400s on Oracle. In 1993, with Oracle losing its franchise to Teletext Ltd, 4-Tel found a new home in the 300s, and had its name shown in the header row. Intelfax continued to produce the service and in 2002 it was renamed FourText.

Teletext on 4
In 2003, Channel 4 awarded Teletext Ltd a ten-year contract to run the channel's ancillary teletext service, named Teletext on 4. The service closed in 2008, and Teletext is no longer available on Channel 4, ITV and Channel 5.