British supermarkets and dairy processors were accused last month of fixing the price of milk, butter and cheese. The British government’s Office of Fair Trading said it believed the sharing of highly commercially-sensitive information in 2002 and 2003 led to an estimated cost to consumers of around 270 million pounds.

The OFT’s case is against Asda, Morrisons, Safeway, Sainsbury’s and Tesco, as well as dairy processors Arla, Dairy Crest, Lactalis McLelland, The Cheese Company and Wiseman.

OFT executive director Sean Williams told the UK media “This is a very serious case. We believe supermarkets have been colluding to put up the price of dairy products.

Consumers have lost out to the tune of hundreds of millions of pounds.”

The OFT said the alleged practice of sharing information restricted the competitive process in the dairy sector, leading to higher prices.

It said the parties understood that their actions might be anti-competitive and said retailers were previously warned of this by the OFT.