As spoken by the Fourth Doctor, A (Morse code: .- (TV: The Man Who Never Was [+]Gareth Roberts, The Sarah Jane Adventures series 5 (CBBC, 2011).) was the first letter of the alphabet, preceding B. (TV: The Masque of Mandragora [+]Louis Marks, Doctor Who season 14 (BBC1, 1976).)
As of 25 December 2006, about one-third of Earth's human population had A-positive blood. (TV: The Christmas Invasion [+]Russell T Davies, Doctor Who Christmas special (BBC One, 2005).)
A levels were a type of exam. (TV: Terror of the Autons [+]Robert Holmes, Doctor Who season 8 (BBC1, 1971)., Dragonfire [+]Ian Briggs, adapted from Seventh Doctor Audition Tapes (Andrew Cartmel), Doctor Who season 24 (BBC1, 1987).)
The first entry in Auteur's Abecedarium claimed that A was for Auteur. (PROSE: Auteur's Abecedarium [+]Jayce Black, The Crew of the Copper-Colored Cupids crossover fiction (Goblin Studios, 2020)., POEM: Auteur and the Homeworld [+]Lupan Evezan, The Crew of the Copper-Colored Cupids crossover fiction (Goblin Studios, 2022).)
In November 1963, science teacher Ian Chesterton set his Coal Hill School class a problem with the letters A, B and C representing the three dimensions. However, Susan Foreman pointed out that he had not acknowledged two additional dimensions: D, which Ian reasoned was time, and E, which Susan revealed was space. (TV: "An Unearthly Child" [+]Part of An Unearthly Child, Anthony Coburn, adapted from The Pilot Episode (Anthony Coburn), Doctor Who season 1 (BBC tv, 1963).)
Contingency Plan A was the name the Company gave to the process of releasing dianene to kill the population of a city. (TV: The Sun Makers [+]Robert Holmes, Doctor Who season 15 (BBC1, 1977).)
While under mental attack by the Mandragora Helix, the Fourth Doctor and Sarah Jane Smith spoke the alphabet backwards to concentrate. (TV: The Masque of Mandragora [+]Louis Marks, Doctor Who season 14 (BBC1, 1976).)
When trying to remember "Young Parsons'" name, Professor Chronotis went through the alphabet with the Doctor and Romana II. They started with A, B, and C and eventually got to P, Q, and R before he skipped to X and Y. (TV: Shada [+]Douglas Adams, Doctor Who (1992)., WC: Shada [+]Douglas Adams and Gary Russell, adapted from Shada (Douglas Adams), BBCi animations (2003).)
As recorded in the Dalek Survival Guide, the 2150s Dalek invasion of Earth involving the First Doctor was part of a version of history "A" relative to "B" and "C". (PROSE: Dalek Survival Guide [+]Justin Richards, et al., BBC Books (2002).)
Rose Tyler got one A, two Bs, four Cs, and a D in GCSE science. (PROSE: Meet Rose [+]Russell T Davies, Doctor Who Annual 2006 (Panini UK, 2005).)
Whilst the pair were surrounded by Geocomtex security guards within Henry van Statten's Vault in 2012, Rose Tyler quipped that the Ninth Doctor would be "Exhibit A" in a hypothetical collection of aliens. (TV: Dalek [+]Robert Shearman, adapted from Jubilee (Robert Shearman), Doctor Who series 1 (BBC One, 2005).)
A set of wooden blocks, with one of them featuring the letter "A". (TV: The Doctor Dances [+]Steven Moffat, Doctor Who series 1 (BBC One, 2005).)
"A" was among the letters written on a set of wooden blocks in Room 802 of Albion Hospital, within which the Empty Child was questioned by Dr Constantine. (TV: The Doctor Dances [+]Steven Moffat, Doctor Who series 1 (BBC One, 2005).)
In 2028, under the influence of Nobody No-One, a cardiogram once sung the alphabet from A to P. (AUDIO: A Death in the Family [+]Steven Hall, Main Range (Big Finish Productions, 2010).)
The Tenth Doctor and the entity possessing Sky Silvestry spoke the first fifteen letters of the alphabet simultaneously. (TV: Midnight [+]Russell T Davies, Doctor Who series 4 (BBC One, 2008).)
In 2010, Amy Pond wore a gold necklace in the shape of the letter "A". (TV: The Eleventh Hour [+]Steven Moffat, Doctor Who series 5 (BBC One, 2010).)
Upon seeing the image of Joseph Serf, actually a hologram, Clyde Langer announced that he was "preparing to say the A word", clarifying to Sky Smith that he meant aliens. (TV: The Man Who Never Was [+]Gareth Roberts, The Sarah Jane Adventures series 5 (CBBC, 2011).)