"Cheerful curiosity can easily become cruelty. It can easily become fatal. We don't cut off the heads of royal ladies these days, but we do sacrifice them, and we did memorably drive one to destruction a scant generation ago."

The institution of monarchy may be irrational, Mantel added, but those outside don't have to forget their principles as they observe the "entertainment" the royals provide.

"I'm not asking for censorship. I'm not asking for pious humbug and smarmy reverence. I'm asking us to back off and not be brutes," she said.

Emily Bell, director of the Tow Center for Digital Journalism at the Columbia Journalism School, defended Mantel via Twitter, saying the furor exemplified the author's point about the media's role.

"The Middleton row is caused by the Mail turning Hilary Mantel's rather wonderful lecture into an example of exactly what Mantel warns of..." she said.