Food sales slowed after a strong Easter boost in April, while clothing and footwear fell below last May 2008's strong sales. Big-ticket product in the homewares and furniture sectors remained difficult.

Non-food non-store sales—Internet, mail order and telephone sales—in May were 7.6 percent higher than a year ago, mirroring the month's slowdown in store sales.

"Sun and bank holidays don't make a recovery," says Stephen Robertson, director general of the British Retail Consortium. "Warm weather and days off produced some good performances for seasonal clothing and outdoor living products, such as gardening goods and summer food and drink. But this May was always going to be difficult because the comparison is with strong May sales last year, which delivered some of 2008's best growth figures.

"The three-month average is up slightly overall but still well down on the rates regularly seen before the slowdown really hit retail a year ago," says Robertson. "Negative results show spring has been extremely difficult for most non-food retailers. The turnaround in sales of big-ticket items, such as furniture and large electronics, which would indicate real change in the mood of customers, still eludes us."

"These figures may look disappointing after last month's positive results were flattered by the timing of Easter, but extremely challenging market conditions, particularly for the non-food sectors, continue," says Helen Dickinson, head of retail at KPMG. "Stronger sales last year—May was the last month to report positive like-for-like growth in 2008—also impacted this month's results. We might have expected better figures, while there are consumers struggling financially due to actual, or the prospect of, job losses, there are also those with greater disposable income due to lower mortgage payments, easing inflation and lower fuel costs. It remains to be seen when those who have cash to spare will feel confident to start spending again."