The volume of non-food retail sales in August fell 0.7%, with all sectors recording decreases.
Between July and August, the volume of retail sales across all sectors also fell by 0.5%, according to the Office for National Statistics.
The year-on-year figures saw volumes for August 0.4% higher than in the same month last year. Non-food stores increased 4.6% year-on-year.
Non-food sales volume in the three months from June to August increased by 2.2%, compared to the previous three months.
Barclays Corporate head of retail and wholesale Richard Lowe said: “The slow down started to show in August with subdued consumer confidence finally filtering through to the high street. The environment is likely to get tougher with next month’s comprehensive spending review weighing heavily on household purses. The one significant increase, which is encouraging, was from e-commerce with a significant rise in online sales.”