i) births and deaths

21 June 1991: death of Ivor Salter, who had three roles in Old Who – the Morok Commander in the story we now call The Space Museum (First Doctor, 1965), Odysseus in the story we now call The Myth Makers (also First Doctor, 1965) and Sergeant Markham in Black Orchid (Fifth Doctor, 1982). But for my selfish purposes, he was also the semi-regular policeman in Here Come the Double Deckers!

ii) broadcast anniversaries

21 June 1969: broadcast of tenth episode of The War Games, ending Season 6 of Old Who. Last regular appearance of Patrick Troughton as the Second Doctor, Frazer Hines as Jamie and Wendy Padbury as Zoe.

21 June 2008: broadcast of Turn Left. Donna is thrust into an alternate universe where the Doctor was killed during the events of The Runaway Bride, and the situation continues to deteriorate until she sacrifices herself to change her previous self’s destiny.

21 June 2010: broadcast of The Last Precinct, twenty-fourth episode of the Australian K9 series. A vigilante group of former police officers discover the Department are upgrading the CCPCs with alien tech. They make a stand by holding Gryffen hostage. K9 and Starkey battle the intruders whilst Darius faces up to his past.

iii) dates specified in canon

21 June 2540: birth of Bernice Summerfield (at least according to the 1999 Big Finish audio Just War).