Asda has refused to confirm or deny speculation it sparked the latest investigation by the OFT into potential price-fixing of food and household products.

Press reports surfaced last weekend that Asda was the whistleblower that prompted OFT raids on all major multiples and leading suppliers including Unilever, Procter & Gamble and Coca-Cola Enterprises last month.

"We are one of a number of retailers and suppliers who are assisting the OFT in collecting information," said an Asda spokesman.

Companies found guilty by the OFT of price-fixing could face potential fines of up to 10% of their turnover.