A war of words has broken out between Nestlé and Mars over which company has the country's biggest selling chocolate bar. Nestlé said ACNielsen research figures for April 1999 to July 2000 show sales of KitKat Chunky outstripping Mars bars by 7% in value and 3% in unit sales. The manufacturer says since the launch of Chunky sales of Mars bars have fallen by 12% in volume. But Mars insists Chunky has never outsold its Mars bar and claimed Nestlé had skewed the statistics. A spokeswoman said: "It is very unusual to quote over a 15 month period. Nestlé has cut the figures to include Kit Kat Chunky's novelty peak after launch last April." She said independent research from Information Resources' Infoscan showed Kit Kat Chunky was worth only 79% of Mars bar in value and 65% in volume. ACNielsen said: "Confectionery products have ridiculously high launch peaks. Mars and Nestlé can probably make the research say what they want it to." {{NEWS }}