Imperious influenced by Polyjuice

[weavingon]

No: HPFGUIDX 45877

I think it's probably just a case of JKR not wanting us to suspect 
that Moody wasn't really Moody at that point.

Or, perhaps, the effect of Polyjuice would cause you to appear to be 
that person (from someone else's perspective) in every 
aspect...including any sort of telepathic persuasion or magic you may 
use while in that form. The intent of the potion is to make others 
belive that you are that person, after all.


That's how it comes across for me at least.