Stacey Dooley investigates why Peru has taken the title of the world's cocaine capital. Her journey starts in Lima where she meets the Brits locked up in Peru's jails for smuggling cocaine to Europe. Travelling into the countryside she then discovers how alarmingly easy it is for cocaine to be grown and produced here. Stacey joins government forces as they launch a major crackdown in an attempt to destroy this multi-million dollar industry - but will the fightback be enough? Finally she travels deep into the rainforest where farmers are growing a new super strain of coca plant. Able to grow in damp jungle conditions it threatens to open up millions of new acres to coca production and flood the world with even greater quantities of cocaine.

• Stacey Dooley