Close, but no cigar!

Billy McMahon succeeded Gorton when Gorton survived a Confidence Motion in the Liberal Party room by one vote, then resigned saying it really wasn't a resounding vote of confidence.
What I'm after is the name & position of the person who precipitated that vote, (it wasn't Billy) and what they did to cause it.

HINT: It didn't involve the nightclub visit....
(so what else did Macca suggest? And who would have been responsible for that?)