2 April 1934: birth of the great Robert Holmes, script editor from Robot (1974-75) to Image of the Fendahl (1977), and author of The Krotons (Second Doctor, 1968-69), The Space Pirates (Second Doctor, 1969), Spearhead from Space (Third Doctor, 1970), Terror of the Autons (Third Doctor, 1971), Carnival of Monsters (Third Doctor, 1973), The Time Warrior (Third Doctor, 1973-74), The Ark in Space (Fourth Doctor, 1975), Pyramids of Mars (1975), The Brain of Morbius (co-author, 1976), The Deadly Assassin (1976), The Talons of Weng-Chiang (1977), The Sun Makers (Fourth Doctor, 1977), The Ribos Operation (Fourth Doctor, 1978), The Power of Kroll (Fourth Doctor, 1978-79), The Caves of Androzani (Fifth Doctor, 1984), The Two Doctors (Sixth Doctor with Second Doctor, 1985), The Mysterious Planet (Sixth Doctor, 1986), and the first episode of The Ultimate Foe (Sixth Doctor, 1986). See Richard Molesworth's excellent biography.
2 April 1940: birth of Peter Haining, who wrote reference books Doctor Who: A Celebration (1983), The Key to Time (1984), The Doctor Who File (1986), The Time-Travellers' Guide (1987) and Doctor Who: 25 Glorious Years (1988)
2 April 2008: death of Johnny Byrne, writer of The Keeper of Traken (Fourth Doctor, 1981), Arc of Infinity (Fifth Doctor, 1983) and Warriors of the Deep (Fifth Doctor, 1984).
2 April 2014: death of Glyn Jones, one of the few people who not only wrote a TV Who story - the story we now call The Space Museum (First Doctor, 1965) - but also appeared on the show as an actor, playing stranded astronaut Krans in The Sontaran Experiment (Fourth Doctor, 1975). See his autobiography.
ii) broadcast and production anniversaries
2 April 1966: broadcast of "The Celestial Toyroom", first episode of the story we now call The Celestial Toymaker. The (invisible) Doctor, Steven and Dodo arrive in the realm of the sinister Toymaker, who forces them to play a deadly form of Blind Man's Bluff.
2 April 1974: filming of the Third Doctor regenerating into the Fourth Doctor.
2 April 1977: broadcast of sixth episode of The Talons of Weng-Chiang, ending Season 14. The Doctor and Leela, with allies Jago and Litefoot, destroy Weng-Chiang and Mr Sin in a massive fire-fight in the laundry.
2 April 2005: broadcast of The End of the World. The Doctor and Rose arrive on Platform One to watch the Sun expanding to destroy the Earth, and are embroiled in a murder plot.
2 April 2007: broadcast of first show of Totally Doctor Who including first episode of The Infinite Quest.