Online retail sales rose 18% year on year in January as etailers achieved a strong start to the year and shoppers spent an estimated £8.1bn online.

IMRG and Capgemini’s latest e-Retail Sales Index revealed that online spending exceeded the index’s growth forecast of 17%.

Excluding travel, online consumers spent £78 on average in January, up by £4 from January 2013. Browser-to-buyer conversion rates were at the highest levels recorded since January 2009.

Capgemini head of retail consulting and technology Chris Webster said: “The high conversion rate recorded in January demonstrates that retailers are continuing to evolve their digital platforms, helping to secure sales by improving the customer journey from browsing right through to purchase.”

The home and garden and health and beauty sectors both recorded year-on-year increases of over 20%.

The travel sector experienced yearly growth of 16%, with a huge December-to-January rise of 233%, the highest month-on-month performance ever recorded in the category.

In separate IMRG study, it revealed up to 50% of fashion retailers’ returns are caused by 10% of their products and showed that the long-term average return rate for online apparel sales is also around 23%.