26 April 1928: birth of Donald Cotton, who wrote The Myth Makers (1965) and The Gunfighters (1966) as well as the novelisations of both stories and of The Romans (1965), three of the best Who novelisations in the range.
26 April 1975: death of Kevin Lindsay, who played Linx in The Time Warrior (1973-74), Cho Je in Planet of the Spiders (1974), and Styre/The Marshal in The Sontaran Experiment (1975).
ii) broadcast anniversaries
26 April 1969: broadcast of second episode of The War Games. The Doctor and friends, including Carstairs and Lady Jennifer, escape in an ambulance but are confronted by Roman soldiers.
26 April 1975: broadcast of second episode of Revenge of the Cybermen. Harry and Sarah are on Voga; the Doctor tries to repair the transmat; and the Cybermen arrive.
26 April 2002: webcast of "Death Comes to Time Part 2", twelfth episode of Death Comes to Time.
26 April 2008: broadcast of The Sontaran Stratagem.
26 April 2010: broadcast of The Cambridge Spy, the sixteenth and in my own view much the worst episode of the Australian K9 series. A freak accident takes Jorjie back to 23 November 1963 (geddit?). K9 and Starkey follow to rescue her and become embroiled in a spy-ring and a race against time to save Darius from never having existed (which would have been such a shame).