Doctor Who has spawned numerous spin-offs as part of the Whoniverse, including comic books, films, novels and audio dramas, and the television series Torchwood (2006–2011), The Sarah Jane Adventures (2007–2011), K9 (2009–2010), Class (2016), Tales of the TARDIS (2023–2024), and the upcoming The War Between the Land and the Sea.[6] Across time and space, the Doctor's many incarnations often find events that pique their curiosity, and try to prevent evil forces from harming innocent people or changing history, using only ingenuity and minimal resources, such as the versatile sonic screwdriver.[8] The Doctor's various incarnations have gained numerous recurring enemies during their travels, including the Daleks, their creator Davros, the Cybermen, and the renegade Time Lord the Master.[9] Doctor Who was originally intended to appeal to a family audience[10] as an educational programme using time travel as a means to explore scientific ideas and famous moments in history.Philip Segal, a British expatriate who worked for Columbia Pictures' television arm in the United States, had approached the BBC as early as July 1989, while the 26th season was still in production.The executive producers of the new incarnation of the series were Queer as Folk writer Russell T Davies and BBC Cymru Wales head of drama Julie Gardner.[44] A BBC audience research survey conducted in 1972 found that, by their own definition of violence ("any act[s] which may cause physical and/or psychological injury, hurt or death to persons, animals or property, whether intentional or accidental"), Doctor Who was the most violent of the drama programmes the corporation produced at the time."[45] During Jon Pertwee's second season as the Doctor, in the serial Terror of the Autons (1971), images of murderous plastic dolls, daffodils killing unsuspecting victims, and blank-featured policemen marked the apex of the series' ability to frighten children.[55] Paul Parsons, author of The Science of Doctor Who, explains the appeal of hiding behind the sofa as the activation of the fear response in the amygdala in conjunction with reassurances of safety from the brain's frontal lobe.[58] The image of the TARDIS has become firmly linked to the series in the public's consciousness; BBC scriptwriter Anthony Coburn, who lived in the resort of Herne Bay, Kent, was one of the people who conceived the idea of a police box as a time machine.[105] The only portion of this in existence, barring a few poor-quality silent 8 mm clips, is the few seconds of the regeneration scene, as it was shown on the children's magazine show Blue Peter.The BBC, in conjunction with animation studio Cosgrove Hall, reconstructed the missing episodes 1 and 4 of The Invasion (1968), using remastered audio tracks and the comprehensive stage notes for the original filming, for the serial's DVD release in November 2006.[135] An example from the classic series comes from The Trial of a Time Lord (1986), in which Michael Jayston's character the Valeyard is described as an amalgamation of the darker sides of the Doctor's nature, somewhere between the twelfth and final incarnation.For 1983's "The Five Doctors", Troughton and Pertwee returned to star with Peter Davison, and Tom Baker appeared in previously unseen footage from the uncompleted Shada serial.[149] The Doctor's first companions seen on-screen were his granddaughter Susan Foreman (Carole Ann Ford) and her teachers Barbara Wright (Jacqueline Hill) and Ian Chesterton (William Russell).[150] Notable companions from the earlier series include Romana (Mary Tamm and Lalla Ward), a Time Lady; Sarah Jane Smith (Elisabeth Sladen); and Jo Grant (Katy Manning).[160] The tenth series included the alien Nardole (Matt Lucas)[161] and introduced Pearl Mackie as Bill Potts,[162] the Doctor's first openly gay companion.[163] The Thirteenth Doctor has primarily travelled with Ryan Sinclair (Tosin Cole), Graham O'Brien (Bradley Walsh), Yasmin Khan (Mandip Gill),[164] and Dan Lewis (John Bishop).The original theme was composed by Ron Grainer and realised by Delia Derbyshire of the BBC Radiophonic Workshop, with assistance from Dick Mills, and was released as a single on Decca F 11837 in 1964.[citation needed] On 26 June 2018, producer Chris Chibnall announced that the musical score for series 11 would be provided by Royal Birmingham Conservatoire alumnus Segun Akinola.Simpson's first Doctor Who score was Planet of Giants (1964) and he went on to write music for many adventures of the 1960s and 1970s, including most of the stories of the Jon Pertwee/Tom Baker periods, ending with The Horns of Nimon (1979).[citation needed] In these films, Peter Cushing plays a human scientist[251] named "Dr. Who" who travels with his granddaughter, niece, and other companions in a time machine he has invented.After the film, he continued the role in audio dramas and was confirmed as the eighth incarnation through flashback footage and a mini episode in the 2005 revival, effectively linking the two series and the television movie.[262][263] In 2010, a fourth season featured Matt Smith as the Eleventh Doctor alongside former companion actress Katy Manning reprising her role as Jo Grant.[267] Class, featuring students of Coal Hill School, was first aired on-line on BBC Three from 22 October 2016, as a series of eight 45 minute episodes, written by Patrick Ness.[284] In 1993, for the franchise's 30th anniversary, another charity special, Dimensions in Time, was produced for Children in Need, featuring all the surviving actors who played the Doctor and a number of previous companions.[290][291] Doctor Who has been satirised and spoofed on many occasions by comedians including Spike Milligan (a Dalek invades his bathroom—Milligan, naked, hurls a soap sponge at it) and Lenny Henry.[292] Doctor Who fandom has also been lampooned on programs such as Saturday Night Live, The Chaser's War on Everything, Mystery Science Theater 3000, Family Guy, American Dad!, Futurama, South Park, Community as Inspector Spacetime, The Simpsons and The Big Bang Theory.[307][305] In August 2020, Big Finish announced a new series of audios beginning release in May 2021, featuring Christopher Eccleston reprising his role as the Ninth Doctor.[323][324] Since the creation of the Doctor Who character by BBC Television in the early 1960s, a myriad of stories have been published about Doctor Who, in different media: apart from the actual television episodes that continue to be produced by the BBC, there have also been novels, comics, short stories, audio books, radio plays, interactive video games, game books, webcasts, DVD extras, and stage performances.