“Taxes are often higher when price-sensitivity is low. For example, the government charges high taxes on petrol and cigarettes, not for environmental and health reasons but because people who buy these products need to drive and are addicted to smoking; they won’t change their behaviour much even in the face of large taxes. (If you think that taxes on petrol are motivated by environmental concerns, think again: despite the environmental impacts of air travel, electricity and domestic heating, 90 per cent of all ‘environmental’ taxes in the UK in 2009 were paid by motorists.)”