Online sales growth just marginally ticked up last month, as the start of the new school year and change of season failed to boost online retailers.

Ecommerce sales rose just 0.6% in September, while the clothing category saw its first negative growth in over two years, with sales falling by 1.2%.

Delving into categories, menswear had the starkest fall in sales, down 22.5%, while womenswear, footwear and accessories all also declined year on year 13.3%, 9.8 and 9% respectively.

IMRG theorised that the fall in clothing in September was reflective “of a number of initiatives that aimed to shift consumer attitudes towards sustainable fashion”.

Health and beauty sales online had the biggest growth during the month, up 16.4%, while the slightly warmer weather also brought an increase in beers, wine and spirits sales, up 15.3%.

The overall sales increase was also below the rolling three-, six- and 12-month averages of 0.1%, 2.3% and 5.3% respectively.

Strategy and insight director at IMRG, Andy Mulcahy, said: “September was another poor month for online sales growth; January-September the index is up just 4.9% versus a start-of-year forecast of 9%. Retailers just seem to be facing so many issues at the moment, with low shopper confidence driving the need to discount and very few categories performing well.

“There is only one possible positive factor, which might seem slightly surprising, that could help stimulate sales growth – Brexit.

“In the six months following the June 2016 referendum result, many expected the economic impact to be negative, but actually a lot of the indicators were stronger than anticipated. If the UK does leave the EU by end of October, while that brings challenges and disruption for businesses, in the short term the average person isn’t likely to notice any immediate impact.

“Given that 2016 precedent, should Brexit happen, there might be a collective sigh of relief that the tedium of hearing about it is finally over. We could see a degree of buoyancy in spending just in time for Black Friday and Christmas, which though temporary could help get retailers through what otherwise might prove a tough peak trading period.”