Whose Line Is It Anyway? was created by Dan Patterson and Mark Leveson in 1988 as a radio show on BBC Radio 4. This early incarnation of the show is notable as being the origin of the show’s tradition of having the performers read the credits in an amusing style; as it was a radio show, it was necessary for somebody to read the credits, and it was decided that it might as well be done as part of the programme proper, rather than being done by a traditional BBC Radio announcer. This approach to reading credits was pioneered by the earlier BBC radio show I’m Sorry, I’ll Read That Again. Indeed the title of the show itself is a comedic riposte to another radio show, What’s My Line, merged with the title of a 1972 teleplay (and eventual theatrical play) Whose Life Is It Anyway?. The radio series consisted of six episodes, with Clive Anderson as host, with John Sessions and Stephen Fry as regulars.
Originally, the producers asked the BBC to move to television; however the BBC was hesitant about this move. By this time, an already eager Channel 4 bought the show. Believing the show would become a hit, Channel 4 ordered 13 episodes for the first series, uncommon in the UK where a TV series often consists of just six episodes in its first year. However, this came as a problem between two cast members. Original plans were to have Sessions and Fry as regulars with the rotation of two performers, but Stephen Fry pulled out as he was often scared performing it on radio, however, Sessions, with some persuasion from Fry, continued his role on the show. With the exception of Sessions in the first series and Stiles and Mochrie starting with the seventh and eighth series (respectively), there were no fixed regulars on the show, though there were many recurring regulars (including Fry).
The British television version lasted for a total of 10 series, with 136 episodes, all of which were hosted by Clive Anderson. The UK show was canceled when the ratings began to slump, but found immediate new life in America when its version aired. One of the early North American broadcasters of the British series was the Canadian youth channel YTV, though many episodes were edited for adult language and content.
Most episodes of the British television programme were primarily shot in London. However, half of the episodes for each of series three and four were taped in New York, and series 10 was filmed entirely in Hollywood in the same studio that would host the American version, Raleigh Studios. This final series was first broadcast only in the U.S. on the Comedy Central cable channel. These episodes shot in the United States were often criticized by both fans and critics as being of a lower quality to the London shot episodes. Reruns of the entire British TV series had been running on Comedy Central since the early 1990s, though some episodes were edited to remove games, rearrange games in a show, or remove content that American audiences may find offensive. Repeats of the British series moved to BBC America in April 2006; however, the network has not shown any episodes taped before 1994.
In the late 1990s, the show was brought to the attention of Drew Carey, who worked with regular Whose Line? performer Ryan Stiles, a co-star on the U.S. TV sitcom The Drew Carey Show. Carey convinced ABC to air test episodes in the United States. The U.S. version of the series became an inexpensive hit (though less so than the British version) and ABC kept Carey on as host, with Mochrie and Stiles as regular performers. Several other performers from the U.K. series also appeared on the U.S. series. The show ran on ABC for eight seasons. In 2013, the CW network revived the U.S. version with Aisha Tyler as host and regulars Stiles, Brady and Mochrie returning.
On 6 March 2011, a special edition of the show was recorded for “24 Hour Panel People”, a marathon of UK panel shows, in aid of Comic Relief. The recording was broadcast live on the Comic Relief website at about 9:30am, and, the edited compilation shows for the event, shown 13–17 March on BBC Three. The performers were Humphrey Ker, Josie Lawrence, Neil Mullarkey, Tony Slattery and David Walliams.