“Three is a magic number.”

In 2017, Peter Capaldi ruined my birthday. He didn’t mean to. By all accounts he’s a very nice man who would never do any such thing on purpose, and besides he didn’t know if my birthday. On that fated day, Doctor Who told the nation via the media of Radio 2’s Jo Whiley show that he would soon be an ex-Doctor Who. The 2017 series would be Capaldi’s last as incumbent star. 

“Three series is the new rock and roll,” a friend texted me shortly after the announcement. He was referring to how, of the twenty first century Doctors, all bar Christopher Eccleston had spent this long as the series lead. Something even more true now in 2023 than it was then.

There are complex reasons for this, not all of which we, the audience, will be aware of. They include the number of episodes and/or period of time the actors were signed up for initially, how those fell into calendar years and transmission ‘seasons’ and attempts, some successful, some not, to get them to stay on. The casting of a new Doctor is, after all, the moment of maximum danger for the series, the moment when it is most likely to go wrong in the eyes of the audience. Even a changing of the guard behind the scenes (producers, writers, directors) is more easily quietly fixed. The departure and arrival of a leading actor, however, is big news. 

Ah yes. The changing of the guard. One of the reasons Capaldi’s departure ruined my birthday was that I had - I can no longer remember why - convinced myself that he was staying, and I was excited by that. Not merely because I enjoy and admire Capaldi’s performance (although I do), but because had he stayed in the role he would have become the first Doctor since Tom Baker to star in the series under two distinct producers/showrunners. Peter Davison, Colin Baker and Sylvester McCoy (excluding brief returns like Time Crash) only played the Doctor under John Nathan-Turner. Eccleston and Tennant under Davies. Smith and Capaldi under Moffat. Since then, Jodie Whittaker has come and gone with her casting showrunner, Chris Chibnall.