In pictures: Andy Duncan's Channel 4 career

January 2004: Greg Dyke was forced out of his post as BBC director general following the publication of the Hutton report. He was replaced by the Channel 4 chief executive Mark Thompson, leaving a vacancy at the top of the publicly owned broadcaster. Here Dyke is surrounded by BBC employees outside Television Centre on the day of his departure Photograph: TOBY MELVILLE/REUTERS

Andy Duncan, who made his name as the BBC's marketing director after a 17-year career with Unilever, was appointed as Channel 4's chief executive in July 2004 Photograph: Getty Images/Getty Images Europe

Duncan's first major policy move was to scrap predecessor Mark Thompson's plan for a merger with Channel Five and reveal that Channel 4 was forecast to face a £100m a year funding gap. With this he kick started an ultimately fruitless campaign to secure some form of assistance - possibly public money - for Channel 4 Photograph: David Levene/Guardian

Peter Dale was head of More4 when the channel launched by in October 2005 as part of Channel 4's drive to expand its digital TV presence Photograph: Dan Chung/Guardian

Pay-TV digital service Film4 became a free-to-air free channel in July 2006, a move later repeated with E4. One of the Channel 4-funded movies broadcast on Film4 is This is England, which starred Thomas Turgoose Photograph: The Kobal Collection/www.kobal-collection.com

The outgoing ITV chief executive Charles Allen used his MacTaggart lecture at the 2006 MediaGuardian Edinburgh International Television Festival to lay into Channel 4 for allegedly abandoning its public remit, heralding a period when the broadcaster faced more scrutiny and criticism from rival broadcasters and politicians Photograph: Murdo Macleod/Murdo Macleod

Criticism of Channel 4 reached a crescendo with the Celebrity Big Brother race row in January 2007. Here Jade Goody talks to Davina McCall about the race row, which caused the biggest single crisis of Duncan's tenure Photograph: Rex Features/PZR

18 January, 2007: Duncan's defence of Celebrity Big Brother at a hastily arranged press conference during the Oxford Media Convention failed to mollify critics, while his penchant for casual clothes also drew flak Photograph: Public Domain/Public Domain

Natalie Schwarz, Channel 4's director of radio, saw her ambitions to launch a Channel 4 radio service dashed when Duncan was forced to pull the plug on the venture he had championed in October 2008 Photograph: Martin Argles/Guardian

In early 2009 Dawn Airey, the chief executive of Channel Five, launched a concerted effort to persuade Channel 4 and the government that a merger should be back on the agenda. Duncan and Channel 4 chairman Luke Johnson firmly and successfully resisted the idea Photograph: Graeme Robertson/Graeme Robertson

The Devil's Whore picked up three RTS programme awards in 2009, a year in which a record haul of awards for Channel 4 shows suggested that the broadcaster is in rude creative health Photograph: Giles Keyte/Channel 4

BBC director general Mark Thompson, who gave a cool response to suggestions that Channel 4 could take a slice of the licence fee or merge with the BBC's commercial arm, BBC Worldwide. However, talks about a Channel 4/BBC Worldwide partnership continue Photograph: Graeme Robertson/Guardian

New culture secretary Bradshaw presented the Digital Britain report to parliament in June 2009. The document failed to resolve the question of Channel 4's future funding, although Duncan says that the broadcaster's "future as a public service network is far more secure now that it was when I took over" Photograph: Dan Kitwood/Getty Images Europe

In August 2009, Channel 4 announced it would be dropping Big Brother after the 2010 series, allowing it to divert £50m a year into new programmes as part of a "creative overhaul". Pictured is one of this year's housemates, Bea Photograph: Channel 4 / Rex Features/FOUR

16 September 2009: Duncan ended weeks of speculation about his future by confirming that he would be leaving Channel 4 by the end of the year Photograph: Martin Godwin/Guardian