Long before Tim Cook became Apple’s boss, when his job was to wring costs out of the company’s supply chain, he learned of a problem with a supplier in China. “This is really bad,” he told his staff. “Someone should be in China driving this.” Thirty minutes later he saw one of his executives sitting at a table. “Why are you still here?” he asked quietly. The executive stood up, drove directly to San Francisco’s airport and bought a ticket to China.

This anecdote, recounted in Walter Isaacson’s biography of Steve Jobs, Apple’s founder, is one of only a few tales in print that offer an insight into the management style of Mr Cook, who took over from Jobs shortly before he died of cancer in October 2011. It is telling. While Jobs, the irascible creative genius behind Apple’s bestselling products, stole the show, Mr Cook, who is both courtly and deeply private, plugged away behind the scenes to cement a relationship crucial to Apple’s soaring success: that with China.