"In this world of sceptical, literate, interconnected worldly-wise consumers who care, even obliquely, about rights and responsibilities, who can check prices and join global boycotts at the touch of a Google button there is no place for Big Food to hide," he said.
Speaking at a CIES summit, Sir Bob said food retailers and manufacturers could feel good about their responsive approach to consumers.
But there was less room for self-congratulation when it came to domination, overweening pride and leaving room for local diversity and competition.
He said much of the wealth generated by supermarkets went back to head office and shareholders rather than to the local community. "Meanwhile, the construction of out-of-town superstores creates a vacuum that sucks resources from the town centres, strangling the heart of the local economy."
Sir Bob said the industry needed to ask itself a number of questions, including whether its brands were bullies. "The signs of the brand bully are everywhere, with big brands buying up smaller brands and eliminating competition. In places like India or South Africa it is near impossible just to get a cup of coffee, you can only get Nescafé."
He also accused brands of being "chameleon-like". And he added: "When challenged for poor ethical behaviour they change names to shield their reputations. Brands have the power and resources to ensure economic might wins over social good, but when they fail they duck behind yet another façade."
According to Sir Bob the industry "should prepare now for change".
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