When Rio Tinto sent its iron ore negotiating team to China in 2009, they stayed in Shanghai’s Four Seasons Hotel. But no one else was on the same floor. Other guests had been placed elsewhere, presumably to facilitate eavesdropping.

Meanwhile, the BHP board was taking added precautions to ensure the safety of chief executive Marius Kloppers when he was engaged in sensitive iron ore price negotiations with the Chinese steel mills in China.