The choice of whether to buy something or not cannot be really ‘free’ if on one side a multinational conglomerate is spending millions upon millions of pounds persuading parents to pour it down their children’s throats, while on the other, if we’re lucky, a tiny not-for-profit campaign group is trying to be heard. And, of course, it’s not just the money spent on conventional advertising. The commercial clout these companies exert stretches into almost every corner of modern life, from product placement in popular TV shows to the sponsorship of major sporting events.