<P> Doctor Who follows the adventures of the primary character, a rogue Time Lord from the planet Gallifrey, who goes by the name "the Doctor". He fled Gallifrey in a stolen TARDIS--"Time and Relative Dimension in Space"--a time machine that travels by materialising into and dematerialising out of the time vortex . The TARDIS has a vast interior but appears smaller on the outside, and is equipped with a "chameleon circuit" intended to make the machine take on the appearance of local objects as a disguise; due to a malfunction, the Doctor's TARDIS remains fixed as a blue British police box . </P> <P> The Doctor often finds events that pique his curiosity as he tries to prevent evil forces from harming innocent people or changing history, using only his ingenuity and minimal resources, such as his versatile sonic screwdriver . He rarely travels alone and often brings one or more companions to share these adventures . His companions are usually humans, as he has found a fascination with planet Earth, and he frequently collaborates with the international military task force UNIT when the Earth itself is threatened . As a Time Lord, the Doctor is centuries - old and has the ability to regenerate when his body is mortally damaged, taking on a new appearance and personality . The Doctor has gained numerous reoccurring enemies during his travels, including the Daleks, the Cybermen, and the Master, another renegade Time Lord . </P> <P> Doctor Who first appeared on BBC TV at 17: 16: 20 GMT on Saturday, 23 November 1963; this was eighty seconds later than the scheduled programme time, due to the assassination of John F. Kennedy the previous day . It was to be a regular weekly programme, each episode 25 minutes of transmission length . Discussions and plans for the programme had been in progress for a year . The head of drama Sydney Newman was mainly responsible for developing the programme, with the first format document for the series being written by Newman along with the head of the script department (later head of serials) Donald Wilson and staff writer C.E. Webber . Writer Anthony Coburn, story editor David Whitaker and initial producer Verity Lambert also heavily contributed to the development of the series . The programme was originally intended to appeal to a family audience, as an educational programme using time travel as a means to explore scientific ideas and famous moments in history . On 31 July 1963 Whitaker commissioned Terry Nation to write a story under the title The Mutants . As originally written, the Daleks and Thals were the victims of an alien neutron bomb attack but Nation later dropped the aliens and made the Daleks the aggressors . When the script was presented to Newman and Wilson it was immediately rejected as the programme was not permitted to contain any "bug - eyed monsters". According to producer Verity Lambert; "We didn't have a lot of choice--we only had the Dalek serial to go...We had a bit of a crisis of confidence because Donald (Wilson) was so adamant that we shouldn't make it . Had we had anything else ready we would have made that ." Nation's script became the second Doctor Who serial--The Daleks (a.k.a. The Mutants). The serial introduced the eponymous aliens that would become the series' most popular monsters, and was responsible for the BBC's first merchandising boom . </P> <P> The BBC drama department's serials division produced the programme for 26 seasons, broadcast on BBC 1 . Falling viewing numbers, a decline in the public perception of the show and a less - prominent transmission slot saw production suspended in 1989 by Jonathan Powell, controller of BBC 1 . Although it was effectively cancelled with the decision not to commission a planned 27th series of the show for transmission in 1990, the BBC repeatedly affirmed that the series would return . </P>

When was the first episode of doctor who aired