From Mr Jon Lane.

Sir, The common factor underlying all the stories in your article “The silent emergency” (November 24) is that sanitation is being transformed from a minor, neglected, charitable sector into a vibrant economically important area of human activity. This transformation is occurring because economists and political decision-makers now appreciate that improved sanitation generates massive economic benefits – in addition to the health benefits that have long been familiar to health professionals but insufficiently persuasive to top politicians.