Up until the summer of 1969, the Doctor’s origins were shrouded in mystery. It fell to Terrance Dicks, Doctor Who’s incoming script editor, to explain those origins in the momentous story that brought Patrick Troughton’s tenure to an end.
“We weren’t absolutely sure, but there had been a possibility Doctor Who was going to finish,” says Terrance, recalling the show’s declining fortunes at that time. “Certainly the first thing I heard when I joined was that they were thinking about replacing it. I felt like a cabin boy on the Titanic. But they just couldn’t find anything better. Eventually they said, ‘All right then, we’ll do another year,’ and got [producer] Peter Bryant to find another Doctor. He cast Jon Pertwee.”