Non-food sales were the worst hit, as consumers continue to face uncertainty about their jobs and incomes.
Information revealed on the DIY/Gardening sector showed sales of pot plants and cut flowers performing well due to Mothering Sunday, and the warmer weather helping the sale of garden care products, plants and outdoor supplies.
British Retail Consortium director general Stephen Robertson said: "This is the worst drop in total sales since we first collected these figures in 1995.
"This is strong evidence of the pressure customers and traders are under – this year’s later Easter is a factor but this fall goes beyond anything that can be explained by that alone."
He attributed the drop to high inflation, low wage growth, mounting fuel and utility costs, falling house prices, higher VAT and tax rises.
"These pressures aren’t going away and the arrival of higher National Insurance is likely to compound them in the immediate future," he added.
KPMG head of retail Helen Dickinson said: "The food sector suffered in the month due to Easter purchasing falling into March last year, thus impacting the overall results.
"However, beyond this the trend continues in a marked downward direction, and non-food continues to struggle, with big-ticket and home-related sectors again being the hardest hit."