UK retail sales fell 1% on a like-for-like basis in March, the third straight month of decline, as rising inflation forced consumers to be prudent with their spending.
The British Retail Consortium (BRC) said that total retail sales fell 0.2% from the same period a year ago, the first fall recorded since August last year.
A rise in the value of food sales was offset by a fall in sales of non-food items, as consumers reserved spending for essential items in an uncertain economic climate.
Food sales increased 1.2% over the three months to March, and non-food sales slid 0.8%.
The BRC said the sales figures were hurt by Easter falling in April this year versus March last year.
Paul Martin, head of retail at KPMG, said: "Easter being later in the year is likely to have contributed to the bleaker picture, alongside the other obstacles facing the sector – especially increased input costs."
"Retailers will be hoping Easter boosts retail sales in April, whether it's shoppers making the most of the holiday or those choosing to spruce up their homes," Martin added.
Total sales in the January to March period were up just 0.1% compared to the previous three months, the slowest growth recorded since the final quarter of 2008.
Sales of women's footwear, jewellery and beauty products increased in March, helped by Mother's Day gift purchases.
BRC chief executive Helen Dickinson said the "marginal growth in food was bolstered by slightly higher shop prices following increases in global food commodity costs and a weaker pound.
"The pressure on prices continues to build, albeit slowly, and will inevitably put a tighter squeeze on disposable income and so to ensure consumers continue to enjoy great quality, choice and value on goods, securing tariff free-trade must be the priority as the Brexit negotiations begin in earnest."
Official figures released last month by the Office for National Statistics (ONS) showed that UK retail sales rose 3.7% from a year earlier in February.