Bills Clinton and Gates, Matt Damon and Chris Martin have all associated their names with campaigns for clean water. But do they mention the faecal contamination and lack of toilets, which make ‘dirty’ water a threat? Never.

‘Goodwill Ambassadors’ are three a penny when it comes to child distress. But the urgent need to tackle the second highest child killer, diarrhoea, by astute deployment of a potty and a basin of soapy water does not fall trippingly from their lips.