There is no higher authority.

“Steven wrote to me today, saying, 'Don't you feel like sticking your head out o…”

“The Doctor: The Fourth Great and Bountiful Human Empire. And there it is: plane…”

“Rose: Who are you then? Who's that lot down there? [The Doctor ignores her] I s…”

“If you are an alien, how come you sound like you're from the north?''Lots of pl…”