Materials scientist and broadcaster, Professor Mark Miodownik, explores how we fell in love with plastic, why we've ended up with oceans of waste blighting the environment and what science and society can do about it.

Programme Three:

Roland Pease hears from Kenya where one of the most stringent bans on plastic bags has been in force for nearly two years, from the US where the reuseable cup has taken off and from Sweden where reverse vending machines give you money back when you return your plastic bottles. And he looks at places where plastic is the best material for the job.

Picture: Bike loaded with empty plastic bottles. Shanghai China, Credit: typhoonski/Getty Images