Consultants at PricewaterhouseCoopers used government secrets to help clients in Australia and the US avoid tax – a scandal that has forced resignations and threatens contracts worth hundreds of millions. The federal government has been warned to reconsider its relationship with the consulting industry, which rakes in billions from the government each year. Reporter Henry Belot on how a series of secretive emails marked “for your eyes only” exposed this scandal, and the government’s overreliance on consulting firms that some call a “shadow public service”