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),^[1] the station is now owned and operated by Channel Four Television Corporation, a public corporation of the Department for Digital, Culture, Media and Sport,^[2] 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.

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.^[3]

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.^[3] 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.^[4]

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.^[5]

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.

The first voice heard on Channel 4's opening day of Tuesday 2 November 1982 was that of continuity announcer Paul Coia who said:

Following the announcement, the channel headed into a montage of clips from its programmes set to the station's signature tune, "Fourscore", written by David Dundas, which would form the basis of the station's jingles for its first decade. The first programme to air on the channel was the teatime game show Countdown, at 16:45 produced by Yorkshire Television. The first person to be seen on Channel 4 was Richard Whiteley with Ted Moult being the second. The first woman on the channel, contrary to popular belief, was not Whiteley's Countdown co-host Carol Vorderman but a lexicographer only ever identified as Mary. Whiteley opened the show with the words:

On its first day, Channel 4 also broadcast soap opera Brookside

At its launch, Channel 4 committed itself to providing an alternative to the existing channels, an agenda in part set out by its remit which required the provision of programming to minority groups.

In step with its remit, the channel became well received both by minority groups and the arts and cultural worlds during this period, especially under founding chief executive Jeremy Isaacs, where the channel gained a reputation for programmes on the contemporary arts. Channel 4 co-commissioned Robert Ashley's ground-breaking television opera Perfect Lives,^[7] which it premiered over several episodes in 1984. The channel often did not receive mass audiences for much of this period, however, as might be expected for a station focusing on minority interest.

Channel 4 also began the funding of independent films, such as the Merchant-Ivory docudrama The Courtesans of Bombay

In 1992, Channel 4 also faced its first libel case by Jani Allan, a South African journalist, who objected to her representation in Nick Broomfield's documentary The Leader, His Driver and the Driver's Wife.^[8]

In September 1993, the channel broadcast the direct-to-TV documentary film Beyond Citizen Kane, in which it displayed the dominant position of the Rede Globo television network, and discussed its influence, power and political connections in Brazil.

After control of the station passed from the Channel Four Television Company to the Channel Four Television Corporation in 1993, a shift in broadcasting style took place. Instead of aiming for the fringes of society, it began to focus on the edges of the mainstream, and the centre of the mass market itself.^[9][10] It began to show many US programmes in peak viewing time, far more than it had previously done. It gave such shows as Friends and ER

In the early 2000s, Channel 4 began broadcasting reality formats such as Big Brother and obtained the rights to broadcast mass appeal sporting events like cricket and horse racing. This new direction increased ratings and revenues.

In addition, the corporation launched a number of new television channels through its new 4Ventures offshoot, including Film4, At the Races, E4 and More4.

Partially in reaction to its new "populist" direction, the Communications Act 2003 directed the channel to demonstrate innovation, experimentation and creativity, appeal to the tastes and interests of a culturally diverse society, and to include programmes of an educational nature which exhibit a distinctive character.^[11]

On 31 December 2004, Channel 4 launched a new look and new idents in which the logo is disguised as different objects and the 4 can be seen in an angle.

Under the leadership of Freeview founder Andy Duncan, 2005 saw a change of direction for Channel 4's digital channels. Channel 4 made E4 free-to-air on digital terrestrial television, and launched a new free-to-air digital channel called More4. By October, Channel 4 had joined the Freeview consortium.^[12] By July 2006, Film4 had likewise become free-to-air and restarted broadcasting on digital terrestrial.^[13]

Venturing into radio broadcasting, 2005 saw Channel 4 purchase 51% of shares in the now defunct Oneword radio station with UBC Media holding on to the remaining shares. New programmes such as the weekly, half-hour The Morning Report news programme were among some of the new content Channel 4 provided for the station, with the name 4Radio being used. As of early 2009, however, Channel 4's future involvement in radio remained uncertain.

On 2 November 2007, the station celebrated its 25th birthday.

It showed the first episode of Countdown, an anniversary Countdown special, as well as a special edition of The Big Fat Quiz

In November 2009, Channel 4 launched a week of 3D television, broadcasting selected programmes each night using stereoscopic ColorCode 3D technology. The accompanying 3D glasses were distributed through Sainsbury's supermarkets.^[14]

On 29 September 2015, Channel 4 revamped its presentation for a fifth time; the new branding downplayed the "4" logo from most on-air usage, in favour of using the shapes from the logo in various forms.

Four new idents were filmed by Jonathan Glazer, which featured the shapes in various real-world scenes depicting the "discovery" and "origins" of the shapes. The full logo was still occasionally used, but primarily for off-air marketing. Channel 4 also commissioned two new corporate typefaces, "Chadwick", and "Horseferry" (a variation of Chadwick with the aforementioned shapes incorporated into its letter forms), for use across promotional material and on-air.^[15][16] On 31 October 2017, Channel 4 introduced a new series of idents continuing the theme, this time depicting the logo shapes as having formed an anthropomorphic "giant" character.^[17]

Before the digital switch-over, Channel 4 raised concerns over how it might finance its public service obligations afterward. It was announced in April 2006 that Channel 4's digital switch-over costs would be paid for by licence fee revenues.^[18]

On 28 March 2007, Channel 4 announced plans to launch a music channel "4Music" as a joint venture with British media company EMAP, which would include carriage on the Freeview platform. On 15 August 2008, 4Music was launched across the UK.^[19] Channel 4 announced interest in launching a high-definition version of Film4 on Freeview, to coincide with the launch of Channel 4 HD,^[20][21] However, the fourth HD slot was given to Channel 5 instead.^[22] Channel 4 has since acquired a 50% stake in EMAP's TV business for a reported £28 million.^[23]

Channel 4 was considered for privatisation by the governments of Margaret Thatcher, John Major and Tony Blair.^[24] As of 2016 the future of the channel was again being looked into by the government, with analysts suggesting several options for the channel's future.^[24]

In June 2017, it was announced that Alex Mahon would be the next chief executive, and would take over from David Abraham, who left in November 2017.^[25][26]

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 remit also involves an obligation to provide programming for schools,^[28] and a substantial amount of programming produced outside of Greater London.^[28]

Channel 4 was carried from its beginning on analogue terrestrial, which was practically the only means of television broadcast in the United Kingdom at the time.

It continued to be broadcast through these means until the changeover to digital terrestrial television in the United Kingdom was complete. Since 1998, it has been universally available on digital terrestrial, and the Sky platform (initially encrypted, though encryption was dropped on 14 April 2008 and is now free of charge and available on the Freesat platform) as well as having been available from various times in various areas, on analogue and digital cable networks.

Due to its special status as a public service broadcaster with a specific remit, it is afforded free carriage on the terrestrial platforms,^[30] in contrast with other broadcasters such as ITV.^[31]

Channel 4 is also seen outside the United Kingdom where it is widely available in Ireland, especially in border counties which have been able to receive terrestrial transmissions from Northern Ireland, as well as on Irish cable networks and Switzerland^[32].

Since 2019, it has been offered by British Forces Broadcasting Service (BFBS) to members of HM Forces and their families around the world, BFBS Extra having previously carried a selection of Channel 4 programmes.^[33]

The Channel 4 website allows Internet users in the United Kingdom to watch Channel 4 live on the Internet.

In the past some programmes (mostly international imports) were not shown.

Channel 4 is also provided by Virgin Mobile's DAB mobile TV service which has the same restrictions as the Internet live stream had. Channel 4 is also carried by the Internet TV service TVCatchup^[34] and was previously carried by Zattoo until the operator removed the channel from its platform.^[35]

Channel 4 also makes some of its programming available "on demand" via cable and the Internet through All 4.

During the station's formative years, funding came from the ITV companies in return for their right to sell advertisements in their region on the fourth channel.

Nowadays it pays for itself in much the same way as most privately run commercial stations, i.e. through the sale of on-air advertising, programme sponsorship, and the sale of any programme content and merchandising rights it owns, such as overseas sales and video sales.

For example, as of 2012 its total revenues were £925 million with 91% derived from sale of advertising.^[36] It also has the ability to subsidise the main network through any profits made on the corporation's other endeavours, which have in the past included subscription fees from stations such as E4 and Film4 (now no longer subscription services) and its "video-on-demand" sales. In practice, however, these other activities are loss-making, and are subsidised by the main network. According to Channel 4's last published accounts, for 2005, the extent of this cross-subsidy was some £30 million.^[37]

The change in funding came about under the Broadcasting Act 1990 when the new corporation was afforded the ability to fund itself. Originally this arrangement left a "safety net" guaranteed minimum income should the revenue fall too low, funded by large insurance payments made to the ITV companies. Such a subsidy was never required, however, and these premiums were phased out by the government in 1998. After the link with ITV was cut, the cross-promotion which had existed between ITV and Channel 4 also ended.

In 2007, owing to severe funding difficulties, the channel sought government help and was granted a payment of £14 million over a six-year period.

The money was to have come from the television licence fee, and would have been the first time that money from the licence fee had been given to any broadcaster other than the BBC.^[38] However, the plan was scrapped by the Secretary of State for Culture, Media and Sport, Andy Burnham, ahead of "broader decisions about the future framework of public service broadcasting".^[39] The broadcasting regulator Ofcom released its review in January 2009 in which it suggested that Channel 4 would preferably be funded by "partnerships, joint ventures or mergers".^[40]

Channel 4 is a "publisher-broadcaster", meaning that it commissions or "buys" all of its programming from companies independent of itself.

It was the first broadcaster in the United Kingdom to do so on any significant scale; such commissioning is a stipulation which is included in its licence to broadcast.^[28] This had the consequence of starting an industry of production companies that did not have to rely on owning an ITV licence to see their programmes air, though since Channel 4, external commissioning has become regular practice on the numerous stations that have launched since, as well as on the BBC and in ITV (where a quota of 25% minimum of total output has been imposed since the 1990 Broadcasting Act came into force). Although it was the first British broadcaster to commission all of its programmes from third parties, Channel 4 was the last terrestrial broadcaster to outsource its transmission and playout operations (to Red Bee Media), after 25 years in-house.^[41]

The requirement to obtain all content externally is stipulated in its licence.^[27] Additionally, Channel 4 also began a trend of owning the copyright and distribution rights of the programmes it aired, in a manner that is similar to the major Hollywood studios' ownership of television programmes that they did not directly produce.

Thus, although Channel 4 does not produce programmes, many are seen as belonging to it.

It was established with a specific intention of providing programming to groups of minority interests, not catered for by its competitors, which at the time were only the BBC and ITV.^[3]

Channel 4 also pioneered the concept of 'stranded programming', where seasons of programmes following a common theme would be aired and promoted together.

Some would be very specific, and run for a fixed period of time; the 4 Mation season, for example, showed innovative animation. Other, less specific strands, were (and still are) run regularly, such as T4, a strand of programming aimed at teenagers, on weekend mornings (and weekdays during school/college holidays); Friday Night Comedy, a slot where the channel would pioneer its style of comedy commissions, 4Music (now a separate channel) and 4Later, an eclectic collection of offbeat programmes transmitted in the early hours of the morning.

In its earlier years, Red Triangle was the name given to the airing of certain risqué art-house films due to the use of a red triangle DOG in the upper right of the screen, dubbed as being pornographic by many of Channel 4's critics, while general broadcasting of films on the station for many years came under the banner of Film on Four prior to the launch of the FilmFour brand and station in the late 1990s.

The following is a list of the 10 most watched shows on Channel 4 since launch, based on Live +7 data supplied by BARB,^[42] and archival data published by Channel 4.^[43]

During the station's early days, the screenings of innovative short one-off comedy films produced by a rotating line-up of alternative comedians went under the title of The Comic Strip Presents. The Tube and Saturday Live/Friday Night Live also launched the careers of a number of comedians and writers. Channel 4 broadcast a number of popular American imports, including Roseanne, Friends, Sex and the City, South Park and Will & Grace. Other significant US acquisitions include The Simpsons

In April 2010, Channel 4 became the first UK broadcaster to adapt the American comedy institution of roasting to British television, with A Comedy Roast.^[44][45]

In 2010, Channel 4 organised Channel 4's Comedy Gala, a comedy benefit show in aid of Great Ormond Street Children's Hospital. With over 25 comedians appearing, it billed it as "the biggest live stand up show in United Kingdom history". Filmed live on 30 March in front of 14,000 at The O2 Arena in London, it was broadcast on 5 April.^[46] This has continued to 2016.

Channel 4 has a strong reputation for history programmes and real-life documentaries.

It has also courted controversy, for example by broadcasting live the first public autopsy in the UK for 170 years, carried out by Gunther von Hagens in 2002, or the 2003 one-off stunt Derren Brown Plays Russian Roulette Live

Its news service, Channel 4 News, is supplied by ITN whilst its long-standing investigative documentary series, Dispatches

FourDocs is an online documentary site provided by Channel 4.

It allows viewers to upload their own documentaries to the site for others to view.

It focuses on documentaries of between 3 and 5 minutes.

The website ^[94] also includes an archive of classic documentaries, interviews with documentary filmmakers and short educational guides to documentary-making.

It won a Peabody Award in 2006.^[47] The site also includes a strand for documentaries of under 59 seconds, called "Microdocs".

Channel 4 is obliged to carry schools programming as part of its remit and licence.^[28]

Since 1957 ITV had produced schools programming, which became an obligation.^[48] In 1987, five years after the station was launched, the IBA afforded ITV free carriage of these programmes during Channel 4's then-unused weekday morning hours.

This arrangement allowed the ITV companies to fulfil their obligation to provide schools programming, whilst allowing ITV itself to broadcast regular programmes complete with advertisements.

During the times in which schools programmes were aired Central Television provided most of the continuity with play-out originating from Birmingham.^[49]

After the restructuring of the station in 1993, ITV's obligations to provide such programming on Channel 4's airtime passed to Channel 4 itself, and the new service became Channel 4 Schools, with the new corporation administering the service and commissioning its programmes, some still from ITV, others from independent producers.^[50]

In March 2008, the 4Learning interactive new media commission slabovia.tv ^[95] was launched.

The Slabplayer ^[96] online media player showing TV shows for teenagers was launched on 26 May 2008.

The schools programming has always had elements different to its normal presentational package.

In 1993, the Channel 4 Schools idents featured famous people in one category, with light shining on them in front of an industrial looking setting supplemented by instrumental calming music.

This changed in 1996 with the circles look to numerous children touching the screen, forming circles of information then picked up by other children.

The last child would produce the channel 4 logo in the form of three vertical circles, with another in the middle and to the left containing the Channel 4 logo.

A present feature of presentation was a countdown sequence featuring, in 1993 a slide with the programme name, and afterwards an extended sequence matching the channel branding.

In 1996, this was an extended ident with timer in top left corner, and in 1999 following the adoption of the squares look, featured a square with timer slowly make its way across the right of the screen with people learning and having fun while doing so passing across the screen.

It finished with the Channel 4 logo box on the right of the screen and the name 'Channel 4 Schools' being shown.

This was adapted in 2000 when the service's name was changed to '4Learning'.

In 2001, this was altered to various scenes from classrooms around the world and different parts of school life.

The countdown now flips over from the top, right, bottom and left with each second, and ends with four coloured squares, three of which are aligned vertically to the left of the Channel 4 logo, which is contained inside the fourth box.

The tag 'Learning' is located directly beneath the logo.

The final countdown sequence lasted between 2004 and 2005 and featured a background video of current controversial issues, overlaid with upcoming programming information.

the video features people in the style of graffiti enacting the overuse of CCTV cameras, fox hunting, computer viruses and pirate videos, relationships, pollution of the seas and violent lifestyles.

Following 2005, no branded section has been used for Schools programmes.

From the outset, Channel 4 did not conform to the expectations of conventional religious broadcasting in the UK.

John Ranelagh, first Commissioning Editor for Religion, made his priority 'broadening the spectrum of religious programming' and more 'intellectual' concerns.^[51] He also ignored the religious programme advisory structure that had been put in place by the BBC, and subsequently adopted by ITV.

Ranelagh's first major commission caused a furore, a three-part documentary series called Jesus: The Evidence. The programmes, transmitted during the Easter period of 1984, seemed to advocate the idea that the Gospels were unreliable, Jesus may have indulged in witchcraft, and that he may not have even existed. The series triggered a public outcry, and marked a significant moment in the deterioration in the relationship between the UK's broadcasting and religious institutions.^[51]

Numerous genres of film-making – such as comedy, drama, documentary, adventure/action, romance and horror/thriller – are represented in the channel's schedule.

From the launch of Channel 4 until 1998, film presentations on C4 would often be broadcast under the "Film on Four" banner.^[52][53]

In March 2005, Channel 4 screened the uncut Lars von Trier film The Idiots, which includes unsimulated sexual intercourse, making it the first UK terrestrial channel to do so. The channel had previously screened other films with similar material but censored and with warnings.^[54][55]

Since 1 November 1998, Channel 4 has had a digital subsidiary channel dedicated to the screening of films.

This channel launched as a paid subscription channel under the name "FilmFour", and was relaunched in July 2006 as a free-to-air channel under the current name of "Film4". The Film4 channel carries a wide range of film productions, including acquired and Film4-produced projects. Channel 4's general entertainment channels E4 and More4 also screen feature films at certain points in the schedule as part of their content mix.^[56]

A season of television programmes about masturbation, called Wank Week, was to be broadcast in the United Kingdom by Channel 4 in March 2007. The first show was about a Masturbate-a-thon, a public mass masturbation event, organised to raise money for the sexual health charity Marie Stopes International. Another film would have focused on compulsive male masturbators and a third was to feature the sex educator Dr Betty Dodson.

The series came under public attack from senior television figures, and was pulled amid claims of declining editorial standards and controversy over the channel's public service broadcasting credentials.^[57]

On 8 March 2007, Channel 4 screened a highly controversial documentary, The Great Global Warming Swindle. The programme states that global warming is "a lie" and "the biggest scam of modern times".^[58] The programme's accuracy has been disputed on multiple points, and several commentators have criticised it for being one-sided, noting that the mainstream position on global warming is supported by the scientific academies of the major industrialised nations.^[59] There were 246 complaints to Ofcom as of 25 April 2007,^[60] including allegations that the programme falsified data.^[61] The programme has been criticised by scientists and scientific organisations, and various scientists who participated in the documentary claimed their views had been distorted.^[62]

Against Nature: An earlier controversial Channel 4 programme made by Martin Durkin which was also critical of the environmental movement and was charged by the Independent Television Commission of the UK for misrepresenting and distorting the views of interviewees by selective editing.^[63][64]

The Greenhouse Conspiracy: An earlier Channel 4 documentary broadcast on 12 August 1990, as part of the Equinox series, in which similar claims were made.^[63][65] Three of the people interviewed (Lindzen, Michaels and Spencer) were also interviewed in The Great Global Warming Swindle

In the Christmas address of 2008, a Channel 4 tradition since 1993, Iranian President Mahmoud Ahmadinejad made a thinly veiled attack on the United States by claiming that Christ would have been against "bullying, ill-tempered and expansionist powers".

The airing courted controversy and was rebuked by several human rights activists, politicians and religious figures, including Peter Tatchell^[66], Louise Ellman^[67], Ron Prosor^[68] and Rabbi Aaron Goldstein^[66]. A spokeswoman for the Foreign and Commonwealth Office said: "President Ahmadinejad has, during his time in office, made a series of appalling anti-Semitic statements. The British media are rightly free to make their own editorial choices, but this invitation will cause offence and bemusement not just at home but among friendly countries abroad".^[69]

However, some defended Channel 4. Stonewall director Ben Summerskill stated: "In spite of his ridiculous and often offensive views, it is an important way of reminding him that there are some countries where free speech is not repressed...If it serves that purpose, then Channel 4 will have done a significant public service".^[70] Dorothy Byrne, Channel 4's head of news and current affairs, also defended the station, saying: "As the leader of one of the most powerful states in the Middle East, President Ahmadinejad's views are enormously influential... As we approach a critical time in international relations, we are offering our viewers an insight into an alternative world view...Channel 4 has devoted more airtime to examining Iran than any other broadcaster and this message continues a long tradition of offering a different perspective on the world around us".^[66]

On 15 August 2013, Channel 4 aired a 45-minute documentary on One Direction and their fans dubbed as "Directioners".^[71] Following the airing, fans across the world complained on social media about the documentary, arguing that this was not a reflection of them.^[72]

4Talent is an editorial branch of Channel 4's commissioning wing, which co-ordinates Channel 4's various talent development schemes for film, television, radio, new media and other platforms and provides a showcasing platform for new talent.

There are bases in London, Birmingham, Glasgow and Belfast, serving editorial hubs known respectively as 4Talent National, 4Talent Central England, 4Talent Scotland and 4Talent Northern Ireland. These four sites include features, profiles and interviews in text, audio and video formats, divided into five zones: TV, Film, Radio, New Media and Extras, which covers other arts such as theatre, music and design. 4Talent also collates networking, showcasing and professional development opportunities, and runs workshops, masterclasses, seminars and showcasing events across the UK.

4Talent magazine is the creative industries magazine from 4Talent, which launched in 2005 as TEN4 magazine under the editorship of Dan Jones. 4Talent Magazine is currently edited by Nick Carson. Other staff include deputy editor Catherine Bray and production editor Helen Byrne. The magazine covers rising and established figures of interest in the creative industries, a remit including film, radio, TV, comedy, music, new media and design.

Subjects are usually UK-based, with contributing editors based in Northern Ireland, Scotland, London and Birmingham, but the publication has been known to source international content from Australia, America, continental Europe and the Middle East.

The magazine is frequently organised around a theme for the issue, for instance giving half of November 2007's pages over to profiling winners of the annual 4Talent Awards.

An unusual feature of the magazine's credits is the equal prominence given to the names of writers, photographers, designers and illustrators, contradicting standard industry practice of more prominent writer bylines.

It is also recognisable for its 'wraparound' covers, which use the front and back as a continuous canvas – often produced by guest artists.

Although 4Talent Magazine is technically a newsstand title, a significant proportion of its readers are subscribers. It started life as a quarterly 100-page title, but has since doubled in size and is now published bi-annually.

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.

Channel 4 has, since its inception, broadcast identical programmes and continuity throughout the United Kingdom (excluding Wales where it did not operate on analogue transmitters). At launch this made it unique, as both the BBC and ITV had long established traditions of providing regional variations in their programming in different areas of the country. Since the launch of subsequent British television channels, Channel 4 has become typical in its lack of regional programming variations.

A few exceptions exist to this rule for programming and continuity:

Some of Channel 4's schools' programming (1980s/early '90s) was regionalised due to differences in curricula between different regions.^[49]

Part of Channel 4's remit covers the commissioning of programmes from outside London.

Channel 4 has a dedicated director of nations and regions, Stuart Cosgrove, who is based in a regional office in Glasgow. As his job title suggests, it is his responsibility to foster relations with independent producers based in areas of the United Kingdom (including Wales) outside London.

Advertising on Channel 4 does contain regular variation: prior to 1993, when ITV was responsible for selling Channel 4's advertising, each regional ITV company would provide the content of advertising breaks, covering the same transmitter area as themselves, and these breaks were often unique to that area.

After Channel 4 became responsible for its own advertising, it continued to offer advertisers the ability to target particular audiences and divided its coverage area into six regions: London, South, Midlands, North, Northern Ireland and Scotland.^[73]

At present, Wales does not have its own advertising region, instead its viewers receive the southern region on digital platforms intentionally broadcast to the area, or the neighbouring region where terrestrial transmissions spill over into Wales.

The Republic of Ireland shares its advertising region with Northern Ireland (referred to by Channel 4 as the 'Ulster Macro') with many advertisers selling products for Ireland here.^[74] E4 has an advertising variant for Ireland, although Northern Ireland receives the UK version of E4.^[74] The six regions are also carried on satellite, cable and Digital Terrestrial.

Channel 5 and ITV Breakfast use a similar model to Channel 4 for providing their own advertising regions, despite also having a single national output of programming.

Despite the Republic of Ireland not being in the UK, Channel 4 has a dedicated variant broadcast on Sky Ireland which omits programmes for which broadcast rights are not held in Ireland.

For example, the series Glee is not available on Channel 4 on Sky in Ireland. In recent years a Republic of Ireland advertising opt-out has been added to this version.

With ITV plc pushing for much looser requirements on the amount of regional news and other programming it is obliged to broadcast in its ITV regions, the idea of Channel 4 taking on a regional news commitment has been considered, with the corporation in talks with Ofcom and ITV over the matter.^[75] Channel 4 believe that a scaling-back of such operations on ITV's part would be detrimental to Channel 4's national news operation, which shares much of its resources with ITV through their shared news contractor ITN. At the same time, Channel 4 also believe that such an additional public service commitment would bode well in on-going negotiations with Ofcom in securing additional funding for its other public service commitments.^[75]

In mid-2006 Channel 4 ran a six-month closed trial of HDTV, as part of the wider Freeview HD experiment via the Crystal Palace transmitter to London and parts of the home counties,^[76] including the use of Lost]]and Desperate Housewives s part of the experiment, as US broadcasters such as ABC already have an HDTV back catalogue.

On 10 December 2007, Channel 4 launched a high definition television simulcast of Channel 4 on Sky's digital satellite platform, after Sky agreed to contribute toward the channel's satellite distribution costs. It was the first full-time high definition channel from a terrestrial UK broadcaster.^[77]

On 31 July 2009, Virgin Media added Channel 4 HD on channel 146 (later on channel 142, now on channel 141) as a part of the M pack.^[78] On 25 March 2010 Channel 4 HD appeared on Freeview channel 52 with a placeholding caption, ahead of a commercial launch on 30 March 2010, coinciding with the commercial launch of Freeview HD.^[79][80] On 19 April 2011, Channel 4 HD was added to Freesat on channel 126.^[81] As a consequence, the channel moved from being free-to-view to free-to-air on satellite during March 2011. With the closure of S4C Clirlun in Wales on 1 December 2012, on Freeview, Channel 4 HD launched in Wales on 2 December 2012.^[82]

The channel carries the same schedule as Channel 4, broadcasting programmes in HD when available, acting as a simulcast.

Therefore, SD programming is broadcast upscaled to HD.

The first true HD programme to be shown was the 1996 Adam Sandler film Happy Gilmore.

From launch until 2016 the presence of the 4HD logo on screen denoted true HD content.

On 1 July 2014, Channel 4 +1 HD, a timeshift of Channel 4 HD, launched on Freeview channel 110.

On 20 February 2018, Channel 4 announced that Channel 4 HD and All 4 will no longer be supplied on Freesat from Thursday 22 February 2018.^[83]

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.

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.^[84] 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 ^[84] and in 2002 it was renamed FourText.

In 2003, Channel 4 awarded Teletext Ltd a ten-year contract to run the channel's ancillary teletext service, named Teletext on 4.^[85] The service closed in 2008, and Teletext is no longer available on Channel 4, ITV and Channel 5.