I know you can’t expect accuracy on television, but I heard this line just half an hour ago: ‘It’s the fault of whose ever stupid idea this was’. Shouldn’t that be: ‘It’s the fault of whoever’s stupid idea this was.’? Are both sentences possible? If not, then please give me the correct one.
Formally, I think “whosever” is one word. oxforddictionaries.com/definitio … er?view=uk calls it “rare”. Based on OneLook results, many dictionaries seem not to list it. To me it looks a bit strange and old-fashioned, but I think we can’t say it is incorrect.
However, it is also possible, in casual speech, to conjure up something that one might imagine would be written “whose ever”, with no deliberate intention to use the rare/literary word “whosever”. I suspect that may be the case here, but it is not completely clear to me how far the casual utterance possibly incorrectly rendered as “whose ever” and the “rare” “whosever” are actually one and the same thing.
I find “It’s the fault of whoever’s stupid idea it was” acceptable in everyday English. Another option would be to say something like “It’s the fault of whoever who had the stupid idea.” In formal English I would probably go more for the latter style (though of course this specific sentence would not be used in a formal setting).