E-commerce in the United Kingdom will increase approximately 11.5% this year, to 87 billion pounds ($138.0 billion) from 78 billion pounds ($123.7 billion) last year, predict global business and technology consultancy Capgemini and U.K. e-retail association Interactive Media in Retail Group. That growth is down from 14% year-over-year growth in 2012, they say.

“In spite of continued tough trading conditions as consumers concentrate on paying down debt, we are forecasting growth as consumers look to get maximum value from every transaction,” says Andrew McClelland, chief operations and policy officer at IMRG.

The report says mobile commerce in the country boomed in 2012, with sales via smartphones and tablets up 304% over 2011, though the Capgemini and IMRG report provide no spending figures. “Its growth in the last 12 months has been staggering,” says Chris Webster, head of retail and technology at Capgemini. “Visits and sales from either a smartphone or a tablet device are nearly four times higher than last year—we are reaching a point where we are spending longer on our phones shopping than making calls.”

Evidence of the growth in mobile device ownership comes from U.K. online and catalog retailer Shop Direct Group, No. 7 in the Internet Retailer Europe 400. Shoppers across its brands bought more than 61,000 tablets in December and 91,000 in the six-week holiday shopping period, the retailer says. And, for the first time, kids’ tablets were the top two items on Shop Direct’s toy bestseller charts in 2012, it says. “Looking back at 2012 as a whole, the big themes of the year were mobile and personalization and both will continue to be at the forefront of our e-commerce strategy for 2013 and beyond,” says Gareth Jones, group retail and strategy director at Shop Direct.

“Customer adoption of m-commerce continued apace both in the run-up to and after Christmas, with sales via mobile devices representing 37% of our total online revenue,” which represents an increase of about 20 percentage points, the retailer adds.

In December 2012, U.K. e-retail sales increased 17.5% year over year, and 12% from November 2012, Capgemini and IMRG say. However, conversions in the last two months of the year—normally expected to rise by about 1%—were down slightly instead, they say. Combined with the season’s strong sales, that decline suggests that U.K. consumers are increasingly using the Internet to research purchases, online and offline, before buying, the organizations say. They add that the continued economic slump in the U.K. could be driving consumers to use the web to seek more deals.