20 May 1926: birth of John Lucarotti, writer of Marco Polo (1964), The Aztecs (1964) and The Massacre (1966).
20 May 1961: birth of Owen Teale who played Maldak in Vengeance on Varos (1985) and Evan Sherman in CountrycideTorchwood, 2006).
20 May 1966: death of Mervyn Pinfield, who was Associate Producer for Doctor Who from An Unearthly Child (1963) to The Romans (1965) and also directed The Sensorites (1964), Planet of Giants (1964) and The Space Museum (1965).
20 May 1977: death of Lennie Mayne, who directed The Curse of Peladon (1972), The Three Doctors (1972-73), The Monster of Peladon (1974) and The Hand of Fear (1976)
20 May 1993: death of William Emms, author of TV story Galaxy 4 (1965) and the widely forgotten Sixth Doctor book, Mission to Venus (1986).
20 May 1996: death of Jon Pertwee, who played the Third Doctor from 1970 to 1974, with occasional returns to the role.
ii) broadcast anniversaries
20 May 1967: broadcast of first episode of The Evil of the Daleks. The Tardis is stolen, and when the Doctor and Jamie pursue it, they find an antique shop with added Dalek.
20 May 1972: broadcast of first episode of The Time Monster. The Newton Institute near Cambridge is in fact run by the Master, who summons Kronos.
20 May 2006: broadcast of The Age of Steel. The Doctor and friends manage to infiltrate Cybus industries and destroy the Cybermen.