A business survey suggests that British retailers were among the losers during the London 2012 Olympic Games.

The Confederation of British Industry's survey released Thursday showed that 31 percent of the sample reported worse sales compared to last year, while 27 percent reported an improvement. That was a shock to analysts, who had been expecting retailers winning extra business during the Games.

The survey, conducted between July 26 and Aug. 15, covered the span of the Games.

The CBI survey tends to move broadly in line with official government data, though there can be significant differences in a given month.