1 May (production)


 * 1969 - David Whitaker was commissioned to write The Ambassadors of Death, then known as The Carriers of Death. Full scripts were requested nearly two months later.
 * 1974 - The final studio recording session for TV: Planet of the Spiders and for Jon Pertwee was held. Tom Baker, already in the midst of production of his first story, attended and filmed a regeneration sequence.