I didn't mean "bizarrely" as a criticism but in a story clearly trailed as a two-parter (as opposed to the is it/isn't it game played last year) I thought it worked surprisingly well as a stand-alone.

The "former prime minister" was an in-joke of sorts. When the character first appeared she constantly introduced herself as "Harriet Jones, MP for Flydale North", displaying her ID card. She carried on doing that when prime minister "Harriet Jones, Prime Minister". I'm not sure extending that to former prime minister really worked though.

There are all sorts of theories flying around about the conclusion mostly because very few people believe a real regeneration could have been kept secret. But we'll see.