The CBI Distributive Trades Survey said 42% of retailers said sales volumes grew year-on-year in the first half of December, 33% said they had fallen. The balance of +8% is the weakest since November 2006 and the fourth month in a row when sales growth disappointed expectations.
The survey was conducted in the early build up to Christmas between November 29 and December 12 so recent discounting and improved footfall could still lift the December month.
Retailers were also pessimistic about sales in January, which they expect to be down on the previous year.
John Longworth, chairman of the CBI's distributive trades panel and executive director of Asda said: "We're coming to the end of what's been a successful year for many on the high street. So sales growth in the first part of December seems relatively more disappointing when compared with last year's pre-Christmas period and the first half of 2007."
"Maintaining consumer confidence is vital, at a time when the extent to which tighter borrowing and the impact of the credit crunch will bear down on people's pockets is still not fully known. Consumer spending will certainly slow next year but the overall economy will stay in reasonable shape," Longworth added.