According to the Office for National Statistics (ONS), total sales volume in the period was just 2.3 per cent higher than the same period a year ago, the lowest growth since April 2006.
Food stores fell 0.1 per cent, the worst result since records began in 1986. Non-food stores increased 3 per cent.
Between August and September, total sales volume decreased 0.4 per cent. Food stores rose 0.3 per cent and non-food fell 1.1 per cent. Non-food includes clothing and footwear stores, and household goods, which fell 2.3 per cent and 2 per cent respectively.
The ONS said the non-seasonally adjusted value of retail sales for the three months to September was 3.5 per cent higher than in the same period a year earlier. The average weekly value of sales in September was£5 billion, 3 per cent higher than in September last year.