For three decades, Mexico’s drug lords have terrorised the country. New documentary Cartel Land tells the story from the inside, exposing the meth labs, the torture, the corruption – and the government collusionOne must hope that audiences appreciate the extraordinary scene with which the documentary Cartel Land opens: deep within a forest in Mexico, a group of men cook crystal meth, and discuss their metier.“We know what harm we do with all the drugs,” muses one of them, masked.