British consumers delegate a higher share of their shopping to the six weeks from mid-November to Christmas Day, and a mixture of bad weather, deep discounts and online shopping has created a tough environment for stores, Bryan Roberts of Kantar Retail told CNBC on Tuesday.
(Read more: Sleigh full of deals to follow slow shopping season)
"The [U.K.] retail sector is tremendously dependent on Christmas," Roberts said on "Squawk on the Street." "We don't have Thanksgiving—which obviously prolongs the holiday shopping season—and retailers are really up against it this year."
(Read more: As the clock ticks, retail traffic continues slide)
Roberts said British retailers can generate up to half of their sales and more than 90 percent of their profits during the six weeks between mid-November and Christmas.
"This concentration on a very small period of time compared to the United States is putting a lot of retailers under enormous pressure," he said.
—By CNBC's Jeff Morganteen. Follow him on Twitter at @jmorganteen and get the latest stories from "Squawk on the Street"