Give 'em an inch... imperial and metric Word of Mouth

Michael Rosen and Laura Wright talk to maths writer Rob Eastaway about imperial and metric measurements. How and why do they co-exist in the United Kingdom? Why are teenagers still talking in feet and inches when at school they are taught in centimetres? And where do the words 'gallon', 'tonne' 'acre' and "yard" come from? Producer Sally Heaven.