The BRC/Springboard footfall in August was 0.9% lower than a year ago, down on the 0.8% rise in July. This is the lowest footfall rate since March 2013.
Footfall in out-of-town locations was flat in August after a relatively strong performance over the last four months.
High street footfall fell 0.6% although this compares with a good performance a year ago. Footfall in shopping centre locations remained weak, down 2.2%, but a slight improvement on July's 2.3% decline.
The North & Yorkshire was the only region to report positive footfall growth, up 0.1%. All other regions and nations reported a decline in footfall.
Helen Dickinson, British Retail Consortium Director General, said: "A slight fall in shopper numbers is disappointing after several months of positive results, but there are a few factors at play. We're comparing against August 2012, when an Olympic influx in some areas pushed up the UK average, and it's also possible that more of us took our holidays after electing to stay put for last year's summer of sport.
"An overall drop masks widespread variations, with only Scotland and the North and Yorkshire showing a higher rate than the UK average. The latter region has the UK's highest vacancy rate, so there's reason to be cautiously optimistic this month.
"All in all, these figures need to be taken in tandem with the recent rosier economic news, including a good run of sales growth and many of us starting to feel more positive about the economy. A small dip in one month shouldn't take the shine off the tentative signs of improving consumer confidence hinted at in recent times, and retailers are working hard to read these conditions so that they can continue to deliver for their customers."