Britain's fourth largest grocer after Tesco TSCO.L, Sainsbury's SBRY.L and Asda said the lower prices cover 6% of its total volume sales. LONDON, April 25 (Reuters) - Against a backdrop of soaring inflation in Britain's food retail sector, supermarket group Morrisons said on Monday it was reducing prices on over 500 products. Morrisons, owned since October by U.S. private equity firm Clayton, Dubilier & Rice, has been the worst performer of Britain's so-called "big four" grocers in recent months, according to industry data.