BBC Four launched on 2 March 2002, with a schedule running from 19:00 to 04:00. The channel shows "a wide variety of programmes including comedy, documentaries, music, international film, original programmes, drama and current affairs ... an alternative to programmes on the mainstream TV channels". It is required by its licence to air at least 100 hours of new arts and music programmes, 110 hours of new factual programmes and to premiere 20 foreign films each year.
BBC Four launched on 2 March 2002 at 19:00 GMT, having been delayed from the original planned 2001 launch. BBC Four began originally as a late schedule to BBC Two, before it received its own channel, along with BBC Three. Curiously, BBC Four had to launch before BBC Three as a result of the government delaying approval plans. The channel replaced BBC Knowledge, an educational and cultural channel which had undergone many changes throughout its lifetime; in its final format it carried a schedule of documentaries and art programming, essentially a test of the new BBC Four schedule. BBC Four would rebrand this channel, and bring it into line with the well recognised BBC One and Two brands at the same time. Planning for the new channel, along with the new BBC Three, had been in progress since October 2000; however, the incumbent government delayed approving the new BBC digital plans. The BBC Four plans were approved earlier, and as a result launched before BBC Three.
BBC Four was different from the old BBC Knowledge: the channel would be more heavily promoted with more new and original programming and the channel would not be broadcast 24 hours a day. This was because on the Freeview digital terrestrial platform, BBC Four is broadcast in a statistically multiplexed stream in Multiplex B that timeshares with the CBeebies channel (which is on air from 06:00 until 19:00). As a result, BBC Four broadcasts from 19:00 to around 04:00 each night, with an hour's down-time and promotions for CBeebies before the start of that channel's schedule.
On 12 May 2011, BBC Four was added to the Sky EPG in the Republic of Ireland on channel 230. It later moved to EPG 211 to free up space for new channels. It later moved to channel 143 on 1 May 2018 to sit beside BBC One Northern Ireland and BBC Two Northern Ireland there, and the 200s being used for +1 channels.
BBC Four forms part of the BBC Vision group, and as a result, the channel controller is answerable to the head of this executive department: Emma Swain, as of 2012. The channel direction is determined by the channel's remit, set by royal charter and the corporation's governing body (the BBC Trust), and by the channel controller. In October 2013, following the departure of Richard Klein from the controllership, the management of the channel changed, with the role of Controller of BBC Four scrapped: from this point the Controller of BBC Two would have ultimate oversight of BBC Four as part of their role, absorbing some of the former duties of the Controller of BBC Four, but a new 'Channel Editor' post, reporting up to this controller, would be created to take day-to-day charge of Four. The controllers of BBC Four from 2002-2016 have been:
Channel Editors of BBC Four have been: