25 April 1923: birth of Paul Whitsun-Jones, who played the Squire in The Smugglers (1966) and the Marshal The Mutants (1972).
25 April 1961: birth of Cyril Nri, who played the Shopkeeper in two Sarah Jane Adventures episodes, Lost in Time (2010) and Sky (2010), and also the Chairman of the Board of Governors in the Class episode The Lost (2016).
ii) broadcast anniversaries
25 April 1964: broadcast of "The Screaming Jungle", third episode of the story we now call The Keys of Marinus. The second Key is hidden in a jungle full of mobile carnivorous plants.
25 April 1970: broadcast of sixth episode of The Ambassadors of Death. The Doctor finds that the aliens are keeping the original astronauts hostage, but is kidnapped by Carrington on his return.