September’s online sales surged 13% on August, revealing the highest ever growth for this period on record and signs of an economic recovery.

The IMRG Capgemini e-Retail Sales Index revealed online sales surged 20% year on year, as the category continued to grow above expectations and consumers shopped on mobile devices.

Almost a quarter – 23% – of mobile device sales were through smartphones in September, up on August when they comprised 15% of mobile sales.

Meanwhile, ahead of the Christmas peak trading period the average basket value reached its highest point since June 2012.

Capgemini vice-president, head of retail consulting and technology Chris Webster said: “This month’s index is a good indicator that we are headed towards economic recovery, and a great sign for a strong Christmas.

“The fact that e-retail has seen its sharpest period of growth for September suggests that consumers are shopping with confidence. In addition, September’s three-year high in the average clothing basket value is a clear sign that retailers are selling through at full price, giving even more confidence to the economic recovery.” 

In September, fashion sales recorded an 18% rise year on year and the highest growth rate in the sector since June. Lingerie sales surged 30%, while accessories and footwear both grew 20%. The index recorded accelerated growth across electricals due to sales of new technologies and smartphones.  

IMRG chief information officer Tina Spooner said: “The record monthly growth in September is an indication of increasing consumer confidence and with smartphone year-on-year sales growth reaching an impressive 150%, it is also evident that shoppers are becoming more comfortable with shopping via their mobile devices.

“Year-to-date the UK e-retail sector has grown 16% compared with the same period in 2012 and we anticipate the sector will continue to record double-digit growth during Q4.”