Figures from the Confederation of British Industry (CBI) show 30% of retailers said sales volumes were up in September on a year ago, while 38% said they were down, giving a balance of -8%.

This was below expectations of +3%, and a decline on August’s balance of +9%.

Lower sales at grocers, food and drink specialists and footwear and leather retailers were the main drivers of the drop in overall volumes.

Strong growth was recorded in clothing, hardware and DIY.

However, retailers expect sales volumes to grow slightly in October.

Data from the Office for National Statistics found retail sales in August increased by more than 6% compared with volumes last year, shrugging off post-Brexit concerns.

Rain Newton-Smith, CBI chief economist, said: “September is normally an important month for retailers and it’s encouraging to see that sales of clothing, DIY goods and hardware are above seasonal norms.

“However, consumer confidence has been dented since earlier in 2016 and higher inflation is likely to squeeze household incomes over the year ahead. With margins remaining tight, retailers are set to continue to operate in a fiercely competitive environment for some time.”