Apple is the most valuable brand on the planet, making products that everyone wants - but how are its workers treated when the world isn't looking? Panorama goes undercover in China to show what life is like for the workers making the iPhone 6. And it's not just the factories. Reporter Richard Bilton travels to Indonesia to find children working in some of the most dangerous mines in the world. But is the tin they dig out by hand finding its way into Apple's products?