British retailers reported the broadest year-on-year decline in sales in more than 40 years as the Iran war raised households' inflation fears, a survey from the Confederation of British Industry showed on Monday. The CBI's monthly retail sales volume measure dropped to -68 in April from -52 in March, its lowest reading since the series started in 1983, as 77% of firms reported sales were down compared with a year ago while only 9% reported an increase.