Cancer, obesity and Boris Johnson’s ‘sin tax’ error

Graham MacGregor says all the evidence suggests taxing unhealthy foods helps reduce their consumption. Plus letters from John Boaler and David Smyth. With Cancer Research UK confirming that obesity is the leading cause of four common cancers in the UK, it’s a scandal that Boris Johnson is questioning the effectiveness of taxes on food and drinks products, and whether taxes unfairly hit those on low incomes ( Obesity rivals smoking as cause of several cancers, warns charity, 3 July). Rather