Meet the Author: Sir John Hegarty on creativity in advertising

Sir John Hegarty is the driving force behind adverts such as the famous Levi's laundrette, the Lynx Effect and Audi's Vorsprung durch Technik.

His latest book, Hegarty on Creativity, pulls together the tips, tricks and advice he has accumulated in his 30 years as creative director of the advertising company he co-founded, BBH.

Sir John spoke to the BBC's Nick Higham about the need for "constant reinvention" in advertising.