Bercow, who attended a comprehensive school, said Eton-educated Cameron has the “most enormous, probably public-school-instilled, self-confidence”.
“He thinks people like him are born to rule, that the natural order is that people like him run things, and that he is in a superior position.”
Bercow refused to say how he would vote at the election – despite representing the Tories before he became speaker.
He stood down as MP for Buckingham at the end of last month after more than two decades in parliament.