Gone are the days when the big four supermarkets dominated the food retail business. Discount stores like Aldi and Lidl are undercutting Tesco, Sainsbury's, Morrisons and Asda, whose sales are stalling and profits are slumping. Harry Wallop asks what went wrong, and is still going wrong, for the major retailers, and reveals the tricks of the discounters' success. He also investigates how the supermarkets are fighting back with an aggressive price war, claiming to have slashed thousands of everyday items. But are these deals all they're cracked up to be?
