Every day 30m tonnes of materials valued at roughly $80bn (€66bn; ￡55bn) are shifted around the world in the process of creating some 1bn types of finished products. Welcome to one of the most complicated mechanisms the human species has yet developed: the global supply chain for manufacturing.

Driven by the emergence over the past 20 years of the opportunity to make products at much lower costs in emerging economies, the supply chain has become a central feature of the global economy.

A main beneficiary has been China, which since 1990 has pushed up its share of global manufacturing as measured by value-added output (the most commonly used way of measuring economic activity) from 2 per cent to an estimated 18 per cent last year. The leap means China now roughly matches the US as the world's biggest manufacturer.