Britain's retail sales quantity including auto fuel decreased by 0.5 percent in May 2014, compared with a month before, said Office for National Statistics (ONS) on Thursday.
Compared with the same month of last year, however, the quantity bought increased by 3.9 percent in May.
To split the industry data, food sales inched up 0.7 percent on year-on-year basis in May, sales in non-food store and non-store retailing increased by 6.0 percent and 18.9 percent respectively, while fuel stores sales decreased by 3.2 percent, said ONS.
In term of the amount spent, retail industry's sales in May increased by 3.2 percent on year-on-year basis, but shrank by 0.5 percent compared with April, data showed.
The amount spent online grew by 15.1 percent in May year-on-year.
Average prices of goods sold in May showed continued deflation of 0.7 percent, with fuel once again providing the largest contribution, falling by 2.2 percent, said ONS.
"Despite the drop in sales volumes back to April levels, the second quarter still looks set to deliver a very strong performance for retailers," said Martin Beck, senior economic adviser to the EY ITEM Club, in a note.
May's fall was the first decline in four months, but following April's rapid rise, some easing was to be expected, according to the analyst.
Beck said that looking forward, Britain's storming rate of job creation, high levels of consumer confidence, as well as a muted pressure on prices, "should sustain further sales growth for the time being."
Samuel Tombs, UK Economist at Capital Economics, commented in an analysis piece that May's retail sales figure showed that a combination of rapid growth and falling prices is continuing to fuel a strong recovery in consumer spending.
"We remain optimistic that a further fall in overall inflation and a recovery in productivity will lift real pay and so provide solid foundation for the recovery in consumer spending soon," he added./.