I'm writing about Queen songs and have encountered some interesting differences of opinion in respect of the time signature of Killer Queen. I have always heard the song in 4/4, as defined by the five clicks at the start of the song and - to my ears - the strong sense of the beat being four crotchets to the bar. The Complete Works book also has the song in Common time.
I was surprised, therefore, to see that advice for students studying the song for exams is that the song is in 12/8. Yes, you can break up the shuffle rhythm into 12 very fast quavers if you want, but I don't think this reflects the feel of the song at all. This is in contrast to, say, Somebody To Love which is undeniably in 12/8, the triplets being all important to the feel of the song.
I presume there isn't a right or wrong answer and, at the end of the day, it's a matter of how the rhythm is heard by the individual. I just can't hear 12 quavers in a bar, especially when the clicks are in such a strict 4/4!