a real world point of view
Innes Lloyd (24 December 1925-23 August 1991) was producer for Doctor Who from the latter part of William Hartnell's tenure as the First Doctor to the middle of Patrick Troughton's second season. With story editor Gerry Davis, he came up with the idea of replacing the character of the First Doctor by what later writers would call regeneration. He also presided over the introduction of the Cybermen.
Lloyd was born in 1925 in Wales. As a producer, he reached the front rank of BBC television drama. He began his television career working on popular series in the 1960s. He was the third producer on Doctor Who. His tenure ran for two seasons, from The Celestial Toymaker through The Enemy of the World (excepting The Tomb of the Cybermen). His most important contribution to the programme was developing the notion of regeneration to replace the lead actor. This arose following continuing health difficulties for William Hartnell.
Lloyd and Gerry Davis came up with the intriguing idea of writing out the character of the Doctor previously known to audiences. John Wiles, the producer preceding Lloyd, had intended to replace Hartnell with another actor playing the same character. Lloyd and Davis elected to modify this idea by adding an in-universe change to the Doctor's personality and appearance. They cast Patrick Troughton after considering character actor Peter Jeffrey for the role. Troughton first appeared in November 1966 after the changeover from Hartnell had been seen at the end of the story The Tenth Planet. That serial also introduced the Cybermen, second only to the Daleks in the Doctor Who monster popularity stakes.
Lloyd oversaw something of a "Monster Era" on the programme. He introduced to it several durable and memorable monsters, including the Ice Warriors and the Yeti. He also introduced the "Base Under Siege" formula, partly as a cost-saving measure for which they could use the same set for much of the story.
Innes Lloyd also worked on Thirty-Minute Theatre, United! and Dead of Night, but he will perhaps best be remembered as the producer of more prestigious drama. His chosen projects were often biographical, and he was a frequent collaborator with Alan Bennett. Bennett's An Englishman Abroad told the remarkable true story of the chance meeting between actress Coral Browne (playing herself) and spy Guy Burgess (Alan Bates) in Moscow in 1958. A Question of Attribution (finished shortly before Lloyd's death) was a logical sequel, showing the radically different fate of Keeper of the Queen's Paintings and fellow traitor Anthony Blunt.