Online retail growth reached a record low during September as high street shops increased promotions, according to the latest IMRG Capgemini e-Retail Sales Index.

Year-on-year growth of eight per cent was the slowest in the history of the Index, while activity in September – which totalled £3.9bn and grew 1.9 per cent compared to August – was considered an “unusually low” rate for that month.

Reasons for the decline include the cautious attitude of shoppers ahead of Christmas, as well as concerns over postal strikes, said the report.

High street retailers placing their bets on the web are trying to downplay the statistics and take action to minimise the impact of any external factors that may put off online shoppers, such as the impending Royal Mail strike.

“Despite the threat of postal strikes, we have ensured that our customers receive an uninterrupted service by switching to other carriers,” said Robin Terrell, managing director at John Lewis Direct.

“Contrary to concerns about the situation leading to an increase in delivery prices, we can guarantee that will not happen at John Lewis. Further, customers can of course continue to enjoy the benefits of our deliver to shop for collection service,” he said.

"It is clear that our customers are increasingly shopping online and enjoying the benefits of our online shopping experience more than ever."

Terrell said that since the relaunch of John Lewis’s fashion site, the department store has enjoyed growth across all its product lines.

The worst performing online sectors during September were clothing, footwear and accessories, as sales growth reached just 10 per cent compared to last year, according to the IMRG study, whereas average year-on-year growth for this sector so far in 2009 has been 20 per cent.