It's being called an environmental catastrophe - that's been followed by an alleged government and industry coverup. The disaster, at a copper mine in Zambia earlier this year, has seen a toxic cocktail of chemicals spill into a river which millions of Zambians live alongside. Channel 4 News has seen a report by an independent body setting out how the true scale of the accident at the mine, which is Chinese owned, has been suppressed. Correspondent: Alex Thomson Producer: Nanette van der Laan Ed