Accountancy and business advisory firm BDO said its monthly High Street Sales Tracker (HSST) found sales in British shops rose 0.7% in December compared to the same month in 2018.
It said the weak outcome was despite an additional shopping day at the beginning of Christmas week.
"Black Friday (Nov. 29) never quite ended and instead saw sales continue throughout the month," said Sophie Michael, head of retail and wholesale at BDO.
“January tends to be a positive month as people are more inclined to spend in the sales, however it’ll be interesting this year to see if many have already done their bargain-hunting in December," she said.
In contrast, online sales in December increased 24.5% year-on-year. Although that was the best monthly performance since December 2013 it was boosted by Cyber Monday falling six days later than it did last year.
BDO's survey made no mention of any impact on sales from Britain's Dec. 12 election which saw Prime Minister Boris Johnson secure a commanding parliamentary majority.
Clothing retailer Next kicked off the Christmas trading update season on Friday, reporting better-than-expected sales and raising its full year profit guidance.
A host of British retailers will report next week, including the UK's biggest player Tesco, along with Sainsbury's, Morrisons and Marks & Spencer's.
(Reporting by James Davey; Editing by Emelia Sithole-Matarise)
