i) births and deaths

13 April 1929: birth of David Fisher, writer of The Stones of Blood (Fourth Doctor, 1978), The Androids of Tara (Fourth Doctor, 1978), The Creature from the Pit (Fourth Doctor, 1979) and The Leisure Hive (Fourth Doctor, 1980).

13 April 1941: birth of Christopher Tranchell, who played Roger Colbert in The Massacre (1966), Steven Jenkins in The Faceless Ones (1967), and Andred in The Invasion of Time (1978). Happy 80th birthday, Chris!

13 April 1951: birth of Peter Davison, who played the Fifth Doctor from 1982 to 1984, and subsequently. Happy 70th birthday, Peter!

13 April 1967: birth of Simon Paisley Day, who played the Steward in The End of the World (Ninth Doctor, 2005) and Rump in Face the Raven (Twelfth Doctor, 2015).

13 April 1984: death of Richard Hurndall, who played the First Doctor in The Five Doctors (1983).

13 April 2015: death of Rex Robinson, who played Dr Tyler in The Three Doctors (Third Doctor plus guests, 1972), Gebek in The Monster of Peladon (Third Doctor, 1974) and Dr Carter in The Hand of Fear (Fourth Doctor, 1977). All three of his appearances were directed by Lennie Mayne.

13 April 2017: death of Eric Pringle, writer of The Awakening (Fifth Doctor, 1984).

ii) broadcast anniversaries

13 April 1968: broadcast of fifth episode of Fury from the Deep. Weed and foam spread throughout the refinery.

13 April 1974: broadcast of fourth episode of The Monster of Peladon. The Pels unite against the Ice Warriors, but the Doctor is unable to prevent Ettis from firing the sonic lance.

13 April 2013: broadcast of Cold War. In 1983, the tensest point of the Cold War, a Soviet submarine discovers a strange creature frozen in the ice of the Arctic. When one of the Firebird's crew breaks it free, it starts attacking…