The much-anticipated Olympics boost failed to cause much of an impression on the high street.
Retailers suffered a "lacklustre" July, with sales values climbing just 0.1 per cent on a like-for-like basis, according to the British Retail Consortium (BRC) and KPMG research.
That compares with a 0.6 per cent rise in the same month last year.
Food and drink sales were helped by the warm weather in the final week and a slight boost from Olympic fever, but that could not offset the impact of lower prices and wet weather earlier in the month.
The BRC said some retailers have done better thanks to the longer Sunday opening hours brought in during London 2012.
So-called big-ticket items such as furniture and household appliances continued to struggle with growth being purely promotion-driven.
Helen Dickinson, head of retail at professional services firm KPMG, said: "Sadly July was a lacklustre month and it's doubtful this trend will change as early expectations that the Olympics will raise retailers' fortunes look to be wide of the mark.
"Central London's retailers are already being hit hard by shoppers actively avoiding the capital. It's likely that any blip of benefit the Games bring will be short-lived."