"I associated surgical instruments with the clean sterile environment of the operating theatre. But here they were being ground and filed by 10 year-old children working full-time in small open garages on the street." New guide launched to improve ethical standards in NHS purchasing.

The book, The Tipping Point, explains how ideas spread and which elements need to come together to help an idea reach a point of critical mass. Have we reached that point in tackling modern slavery?