The UK's biggest supermarkets have been accused of cheating British shoppers out of nearly three hundred million pounds. The Office of Fair Trading claims supermarket giants Asda, Tesco, Sainsbury and Morrisons are guilty of price fixing the cost of milk, cheese and butter. It is claimed that in 2002 the supermarkets colluded with dairies to keep the price of goods artificially high. If found guilty they could face big fines. The supermarkets have denied all the allegations.