Cocaine production has surged across Latin America and unleashed a wave of violence, population displacements and corruption, prompting urgent calls to rethink the drug war.More than 750 tonnes of cocaine are shipped annually from the Andes in a multi-billion pound industry which has forced peasants off land, triggered gang wars and perverted state institutions.A Guardian investigation based on dozens of interviews with law enforcement officials, coca farmers, refugees and policymakers has yield