The latest figures from the IMRG Capgemini e-Retail Sales Index reveal that online sales in the UK exceeded £100bn for the first time in 2014.

Online retail grew 14% last year compared with 2013 as shoppers spent £104bn on ecommerce.

The increasing popularity of online retail shows no signs of slowing down. IMRG and Capgemini forecast that online sales will increase a further 12% in 2015, to account for £116bn of retail sales by year-end.

Capgemini’s principal head of retail consulting Adgild Hop said: “When we consider that almost £1 in every £4 is now spent online, and that a large proportion of the other £3 is influenced by some form of digital interaction, it becomes very clear that retailers need to continue to embrace the opportunity that e-retail poses.”

Over the Christmas shopping period as a whole, defined as the eight weeks between November 2 and December 27, shoppers spent £21.6bn, an increase of 13% from the same period in 2013. Sales through smartphones and tablets saw the most dramatic rise as shoppers spent £8bn with their mobiles over the Christmas period, increasing 55% on the same period in 2013.

Nevertheless, online retail in December recorded only 5% year-on-year growth. That is the lowest ever growth in the Index for this period, as discounting around Black Friday focused huge volumes of sales on the final week of November.

“The challenge going forward is that Black Friday has been cemented into shoppers’ consciousness and they will expect the same kind of focused discounting next year. As an industry, we will need to work together to understand how this extreme activity spike can best be managed in the interests of both shoppers and retailers” said Tina Spooner, IMRG’s chief information officer.

John Lewis’s online director Mark Lewis said: “There is no doubt that this year highlighted a new shape of trade over the Christmas period. Black Friday was John Lewis’s biggest ever week for sales in our 150 year history […] during the early hours of trading there was a 300% increase in traffic to the John Lewis website.”