Tesco yesterday broke ranks to declare it would fight the Office of Fair Trading's provisional ruling that the industry colluded to push up milk prices, as rival retailers and dairy processors agreed to pay a total of £116m in fines.

Britain's biggest supermarket chain stood firm as Asda, J Sainsbury, Robert Wiseman and Dairy Crest admitted they had taken part in "anti-competitive" behaviour in 2002 and 2003 that cost consumers an estimated £270m.