There is one accent that is often rated as the most prestigious - Received Pronunciation. But what is RP and how did it come about? Lynda Mugglestone is a Professor of the History of English at the University of Oxford and author of '‘Talking Proper: The Rise of Accent as Social Symbol'. She says the idea of one national accent for all first started to emerge in the late 1700s with the creation of orthoepy and the invention of pronouncing dictionaries.