The latest figures from IMRG and Capgemini show that online sales rose by five per cent in January compared with the same month last year, reaching £4.3 billion.
However, sales fell by 22 per cent between December 2009 and January 2010, a higher than average monthly drop, the IMRG Capgemini e-Retail Sales Index reveals.
Tina Spooner, director of information at IMRG, attributes the decline to the VAT increase, which took place last month, as well as fewer cases of retail discounting, the Guardian reports.
IMRG and Capgemini's figures show multichannel retailers appeared to see a steeper drop in web sales than their online-only counterparts.
Despite the sharp fall in sales, however, Bruce Fair, managing director of Kelkoo UK, predicts that the online sector will see an upturn in its fortunes later this year.
He says: "Despite a significant slowdown in January, we are still predicting solid growth in the e-retail sector this year, with the market expected to grow by 12 per cent."
Last month, research conducted by the Centre for Retail Research on behalf of Kelkoo suggested that Britons spend the most on online shopping out of all consumers across Europe.
Some £38 billion was spent on purchases made from ecommerce sites last year in the UK, equating to £1,102 per shopper on average.
