If the price tag on an item seems too good to be true, that is usually because there is a hidden cost. Cheap shoes wear out quicker; cheap cars break down sooner. Increasingly, however, consumers are looking not only at the hidden costs to themselves, but at the effect their purchases have on the environment and the people who produce the goods they buy. The global coffee market is, for example, undergoing a gradual but substantial transformation thanks to recognition of the fair trade principle. Supermarket chains have responded to demand for food that is labelled in such a way as to inform consumer choice, not just on nutrition, but on place of origin. Those measures might not be perfect, but as evidence of a cultural change, they are significant. The next sector to undergo that transformation is surely clothing. In the last four years, average prices in retail fashion have fallen by 10 per cent. Outsourcing manufacture to countries with low labour costs in the developing world has fuelled a high street clothing boom. There have followed allegations that low prices are only possible because garments are produced in appalling conditions – sweatshops exploiting child labour. […]