The reasoning behind the timing of the announcement points directly from the edict of the Time Lords, which has long stated that Time Lords can only regenerate only 12 times
before they die. Armed with the knowledge that the current Doctor, Matt Smith, is the 11th regeneration and thinking back to the 1976 episode, “The Deadly Assassin”, in which Tom Baker, the 4th Doctor, revealed even the Doctor’s mortality due to the regeneration limit, the BBC leapt into action.
Seems as though “The Beeb” has chosen a two-part CBBC series, Sarah Jane Adventures, appropriately titled “Death of the Doctor”, which will be telecast in late October, to break the news. Guest star Matt Smith will be engaged in a conversation with Clyde Langer and state, in passing, that there is no limit to his ability to regenerate. That’s it. Move on to the next scene. Not something that is making Who-fans worldwide happy that it’s so glossed over as it is.
Like it or not, now that we’ve settled the Doctor’s immortality, it’s time to deal with Harry Potter and get that eighth book written…