Since it hasn’t been posted yet, Rigg’s character was so named because, having “it” (sexiness) back in the early 60s was described as “man appeal” or, abbreviated “m appeal”.
That’s how Emma Peel got her name.
Now thats an interesting bit of trivia.
That is truly interesting
She was also the inspiration of the spoof character Mrs. Kensington in the 1997 film Austin Powers.