High Street sales fell in December for the fourth year in a row, as shoppers shifted more Christmas shopping online.
Sales were 0.1% lower than in December 2015, according to BDO's High Street Sales Tracker, with consumers spending more on home wares but less on fashion.
However, online sales were 19% higher than a year earlier.
And the tills in High Street stores rang loudly in the week up to Christmas Day - sales rose 11.7% compared with the same week in 2015.
BDO said retailers benefited from Christmas day falling on a Sunday.
Online orders saw an even steeper rise for the week to 25 December, up 51.1%.
Online sales make up about 15% of all retail spending.
During the first three weeks of December fewer shoppers visited the High Street, retail parks and shopping centres.
But they returned in the final week leading up to Christmas day, splashing out on items for the home as well as "lifestyle" items such as bicycles and seasonal products such as wrapping paper and Christmas cards.
Some of December's spending may also have been brought forward to November by sales offers around Black Friday. BDO reported higher year-on-year in-store sales for October and November.
For its High Street Sales Tracker, BDO takes weekly sales figures from 70 participating High Street retailers with about 10,000 stores in total, and compares the percentage change in turnover with the previous year.
The slight decline in High Street sales this December was particularly disappointing, BDO said, given that it was being compared with December 2015 which itself saw High Street sales falling 5.3% compared with 2014.
"With such a weak base for December 2015, any further decline can only be seen as a poor result for retailers," said Sophie Michael, Head of Retail and Wholesale at BDO.
"Coming at a critical juncture, this fourth negative December in succession highlights the magnitude of the challenge that lies ahead for 2017, when consumers will more keenly feel the bite of inflation and the weaker pound."