Purchases made on mobile devices will amount to £373m this Christmas, according to new research from eBay, conducted by Conlumino – but that number could apparently have been much higher if 4G had been rolled out universally.

eBay forecasts that, if the UK had 4G nationwide by the Christmas shopping period, spend on mobile could have reached £493m. That means that slower connection speeds, which eBay identifies as one of the top three barriers preventing consumers from shopping on mobile, will essentially cost the UK economy £120m.

“Mobile devices have become virtual stores in our pockets, giving us the ability to shop anytime, anywhere. But for consumers, it’s critical that the experience is quick, seamless and simple. Slow browsing speeds and breaking connections are now significant barriers to mobile commerce – and this comes at a high price,” said Clare Gilmartin, vice president of eBay Marketplaces, Europe. “While we welcomed the move by Ofcom to bring the 4G spectrum auction forward to early 2013 there’s no doubt, as this research shows, that for the UK economy the cost of another Christmas without universal 4G is huge.”

Its not all bad news though. 55 per cent of consumers plan to browse the web on their mobile device more than they did last year, and 39 per cent say theyll use their mobile to get inspiration for gift ideas and to check prices or product details.

eBay itself, meanwhile, expects to see around a third of items bought from its UK site during its Christmas campaign coming via a smartphone.