British retail sales fell last month in May for the first time since January despite strong sales of World Cup football shirts, data from the Office for National Statistics (ONS) showed on Thursday.

Month-on-month the quantity bought fell by 0.5 percent in May compared with April 2014, said ONS.

Feedback from retailers has suggested that the increase in sales in May was due to the build-up of the FIFA World Cup, said ONS. The fall would have been even bigger had it not been for strong sales in sports stores driven by football shirt sales.

But year-on-year estimates of the quantity bought in the retail industry continued to show growth in May, said ONS. The quantity bought increased by 3.9 percent compared with May 2013.

A better picture of the impact of the World Cup on retail sales statistics would be available when June data are released on July 24, according to the institute.