Nothing concentrates the mind of a foreign executive in China quite so effectively as hearing that four employees of a powerful multinational company have been accused of spying in a case that involves commercial negotiations.

So news of the detention of four employees of Rio Tinto, the Anglo-Australian miner, has spooked multinational mining groups and anyone who does business with the notoriously murky Chinese iron ore and steel industries. But it has also made foreign executives in other industries – even the squeaky clean ones – think twice about their business methods.