How can you make normal TV look 3D?

Pavel got in touch to ask "Take sunglasses and remove one lens. Watch a normal television film with one eye darkened by a sunglass lens, and the other free. The film will appear in 3D. Can someone explain to me, how does this work?" After dusting off her sunglasses, Eva Higginbotham put the question to 3D vision expert Andrew Glennerster from the University of Reading...