巧克力：苦涩的真理

<p>We spend more on chocolate each year than investors spend on gold - but as Easter approaches, how much do we really know about where it comes from or how it is made? Panorama reporter Paul Kenyon goes undercover as a cocoa trader in West Africa and discovers children as young as seven working long hours on cocoa farms, helping to make the chocolate we love so much. He buys a to...</p>