Here's the latest in Tate's series of short films Unlock Art. "How to bluff your way in art" would be a better title, but this has already been used. In Unlock Art: A Brief History of Art Undressed (2014) Dawn O'Porter gives us what Tate describes as a "whistle-stop tour" of nudity in art. It begins 25,000 years ago with The Venus of Willendorf and bounces across centuries to culminate in the dire tripe of Francis Bacon. To be rude with a nude or not to be, that is the question. And who writes the rules?