20 April (releases)


 * 1968 - Episode six of Fury from the Deep was first broadcast on BBC1.
 * 1968 - Part four of the TV Comic story The Cyber Empire was first published.
 * 1972 - The Making of Doctor Who was first published by Piccolo Books.
 * 1974 - Episode five of The Monster of Peladon was first broadcast on BBC1.
 * 1974 - Part seven of the TV Comic story Is Anyone There? was first published.
 * 1978 - Doctor Who Discovers: Strange and Mysterious Creatures was first published by Target Books.
 * 1989 - The novelisation of Attack of the Cybermen was first released by Target Books.
 * 1995 - Sanctuary was first published by Virgin Books.
 * 2005 - The website U.N.I.T. was launched.
 * 2006 - TDW 2 aired on BBC One.
 * 2007 - TDW 16, including episode three of The Infinite Quest, first aired on CBBC.
 * 2011 - DWDVDF 60 was first published by GE Fabbri Ltd.
 * 2011 - AFL 1 was first released by IDW Publishing.
 * 2013 - Hide was first broadcast on BBC One.
 * 2013 - The second edition of The Nth Doctor was published by iUniverse.
 * 2016 - TCH 67 was first released by Hachette Partworks.
 * 2017 - The Shining Man, Diamond Dogs and Plague City were first published by BBC Books.
 * 2017 - Dethras was first released by Big Finish Productions.
 * 2017 - DWFC 96 was first released by Eaglemoss Collections.
 * 2022 - The Torchwood One audio anthology Nightmares was first released by Big Finish.
 * 2022 - The Doctors React to 'Legend of the Sea Devils'  was first released on the Doctor Who Twitter account.