"Now more than ever, we must be the customer's champion. Deliver for the customer and you will survive," he said.
Although the Tesco CEO declined to predict the end of the recession, describing the situation as "fluid", he said retailers should see it as an opportunity.
During the last recession, Tesco reinvigorated its business with initiatives such as the Value range, Clubcard and new store formats, he said. He urged other retailers to take risks - "not risks that gamble the whole company, but measured risks".
He warned retailers not to "lose sight of simple truths". Each sale was a signal to produce more of that product, he said. "Find a business that responds to those signals and you have found a successful company."