According to the trade returns, the advanced industrial economy of the United Kingdom is regularly supplied by the developing countries with aero-engines, scientific instruments, radar installations, and other technologically advanced products, plus a considerable range of more traditional but still sophisticated machinery and equipment. The explanation is that the compilers of our trade statistics have until recently failed to distinguish between goods genuinely imported from abroad and goods in British ownership re-imported after a period of use abroad. It has only been possible to guess at the magnitude of the trade involved.