21 February (releases)


 * 1970 - Episode four of Doctor Who and the Silurians was first broadcast on BBC1.
 * 1970 - Part six of the TV Comic story The Arkwood Experiments was first published.
 * 1976 - Episode four of The Seeds of Doom was first broadcast on BBC1.
 * 1976 - Part four of the TV Comic story Virus was first published.
 * 1980 - The novelisation of The Invasion of Time was first published by Target Books.
 * 1981 - Episode four of The Keeper of Traken was first broadcast on BBC1.
 * 1992 - Episode four of The Mind Robber was repeated on BBC Two.
 * 2007 - The Doctor Who: Battles in Time comic story Beneath the Skin was first published.
 * 2008 - Issue two of Torchwood Magazine was first published by Titan Magazines.
 * 2008 - Part one of the Doctor Who Adventures comic story The Old Kings of Skarab was first published.
 * 2013 - The Doctor Who Adventures comic story Toothache! was first published.