The BRC-KPMG Retail Sales Monitor showed a 1.5% increase in total sales in June, but this was down on the 3.4% increase seen in June 2010.
Like-for-like sales were down 0.6% against a 1.2% rise in June 2010.
Internet, mail order and phone sales grew 11.5%, compared with an 18% rise a year earlier.
Director general Stephen Robertson said: “Given June’s spate of shop closure announcements and weak company results, these figures are not as bad as they could have been, but it shows just how tough times are when total sales growth of 1.5% is regarded as not that bad.
“The higher VAT rate is making year-on-year comparison look better than it really is, while retailers are coping with higher costs because of increased utility bills, rates and the burden of regulation.”